CA2046297A1 - Network system for data transmission - Google Patents
Network system for data transmissionInfo
- Publication number
- CA2046297A1 CA2046297A1 CA002046297A CA2046297A CA2046297A1 CA 2046297 A1 CA2046297 A1 CA 2046297A1 CA 002046297 A CA002046297 A CA 002046297A CA 2046297 A CA2046297 A CA 2046297A CA 2046297 A1 CA2046297 A1 CA 2046297A1
- Authority
- CA
- Canada
- Prior art keywords
- coupled
- adapter
- data
- unit
- network system
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/44—Star or tree networks
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/42—Loop networks
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/14—Two-way operation using the same type of signal, i.e. duplex
- H04L5/1423—Two-way operation using the same type of signal, i.e. duplex for simultaneous baseband signals
Abstract
ABSTRACT OF THE DISCLOSURE
The invention relates to a network system for data transmission between two data processing units, e.g. a peripheral unit (PE) and a Token Ring network with a cable concentrator. Full duplex transmission is effected over each transmission channel between the two data processing units.
For this purpose, the transmission channel comprises a two lead connection (KOAX) with an adapter (APE, AMAU) on either side. One of the adapters is coupled to a peripheral unit and the other to the media access unit (MAU). Each adapter has a transmitting file (TS, TS') for receiving data which is to be transmitted on the two lead connection to the other adapter, a receiving file (TM, TM') for transmitting data to its coupled unit after being sent over the two lead connection from the other unit, and a sorting coupling (TB, Rb, 2; TB', Rb', 4) which sorts out the data on the two lead connection which the adapter has not sent out thereon itself, and feeds this data to the receiving filed (TM, TM').
The invention relates to a network system for data transmission between two data processing units, e.g. a peripheral unit (PE) and a Token Ring network with a cable concentrator. Full duplex transmission is effected over each transmission channel between the two data processing units.
For this purpose, the transmission channel comprises a two lead connection (KOAX) with an adapter (APE, AMAU) on either side. One of the adapters is coupled to a peripheral unit and the other to the media access unit (MAU). Each adapter has a transmitting file (TS, TS') for receiving data which is to be transmitted on the two lead connection to the other adapter, a receiving file (TM, TM') for transmitting data to its coupled unit after being sent over the two lead connection from the other unit, and a sorting coupling (TB, Rb, 2; TB', Rb', 4) which sorts out the data on the two lead connection which the adapter has not sent out thereon itself, and feeds this data to the receiving filed (TM, TM').
Description
~v()~ )s7l~ r~c-l/s~:9(~/()()(~7h X(~4~2~37 N~tw rk sYstem for data transmi~ion The present invention relates to a network ~y~te~ of the type described in the preamble to claim l.
Office data ~roce~6ing sy6tem~ often involve expensive cable inseallation between a central computer and a number of terminals, callad peripheral units below. Different type~ of data processing ~ystems require different types -, of cables. A change in data processing ~ystem o~en requires re-laying the cables with the accompanying cost thereof.
~_' There are star networks, in which all ~he peripheral units are connec~ed to a central uni~ by individual cables. If some fault arises in a peripheral unit, the other peri-pheral units in the system are not affected. Connecting anew peripheral unit i8 done simply by connecting an addi-tional cable to the central unit.
one disadvantage of this peripheral system is ~hat the 23 flow of data between the various peripheral units i8 adminis~ered by the central unit, which decrea~es the effectiveness of the system if data is to be sent b~tween -J the various peripheral units. Another disadvantage i8 $hat expansion with numerous peripheral uni~s requires numerouE
- 25 ports in the central unit, making it expensive. Further- ::
more, there iB a limit to what the cen~ral unit can administer.
one example of a star network i8 the IBM 3270 system, which use~ an RG 62 coaxial cable between the ~entral unit ;. and the peripheral unit. Transmis6ion is half duplex. The SS 3 network in Alfaskop( ) is a staE network which normally uses æhielded double lead but which can also use RG 6Z coaxial cable.
: . ,,~ .. . , . , :
- , : ~ ,. . : . : :~ : .
.. ~ . . : . . . . .. : . . .. : :
: . . . .. . . . :. ~ . - - :
: ~ ~ .: . . : .
woso/os7l2 PC~/SE')IJ/00076 2 21)46~9'7 ~h~r~ ar~ ~rl~ coupled rinq networks which have the advantaqe that the flow of data in the ring pa~e~ all the peripheral units without any controlling central unit. The di~advantage6 are that a 6eries linked ring i6 difficult to expand or change and it is le6s reliable. Since all the peripheral unit~ are connected in serie~ in the ring, addition o~ another peripheral unit requires new cable6 between the units. Removal of a peripheral unit from the ring i~ al60 difficult, ~ince the ring mu~t be broken.
Since there iB no central point where the cables converge, problem~ can spread throughout the entire ring. A ~imple two conductor cable or a coaxial cable can be usad, ~ince the flow of dat~ iB alway6 in the 6ame direction in the ring, i.e. the tran6mi66ion i8 BimpleX.
There are also staL linked ring network6, which re~ain the advantage of serie6 link data flow between the peripheral unit6 but avoid ~ome of the di~advantages of the aeries linked network.
In a ~ta~ linked network, there i~ a cable for each peripheral unit ~o a central point, where a ~o-called cable concentrator is located. The cable concen~rator contains only media acces6 units with relay6 and relay contacts with a relay for each cable. The relay can connect the cable to the ring on order from the peripheral unit and i~ a fault ari6e~ it can disconnect the cable from the ring. If the cable i~ ronnected, it i~ thu~ a portion of the ring, and thi3 require~ a cable with two pairs of conductors. The eran~mis~ion through the ~able is full duplex. When the cable iB di~connected, the ring i~
rerouted internally in the cable concentrator.
one example of thi~ type of network i~ the ~o-called Token Ring, which use6 a shielded twin lead between the cable concentrator and the peripheral unit6.
.
.~
: :-- , .
Replace~lellt ~heet 3 2046~97 If a user, who presently has a star net~vork installed, for ex~mple a 3270 system, wishes to install a Token Ring ~ystem, all of the cables must be replaced with a twin cable, e.g. of I:BM
type. This i9 of~en quite expen~ive and time con~uming, especiaIly in buildiIIgs not pro~ded ~nth space for cable~.
If it were possible to use the e2~st~g cables, this would be a great advantage. Since the Token Ring system operates ~t a trnasmission speed of 4 Mbits/~econLd or 16 Mbita/~econd, this requires a coa~;ial cable, at lea~t for longer distauce~.
e~io~ dec ~o pro~iae a system where exist~ng installed cables for a ~tar ~etwor~, e.g. ~hielded tWill lead cable or coagial cable with single conductor~, can be u~ed in installing a data proCeSSiDg system requinng a cable with at le~t two pairs of lead~.
The abovemen~ioned purpose ~ achieved according ~o the inventio~ w~th an arrangement having the characteri~ic~
disclosed ~ cla~m1. Further ~eatures and deve30pments ~re disdosed in the subclaims.
The invention is, however, applicable to a~y type of point-to-poi~t comlection between two unit~ with baae band 2 5 tran~ rnis~ion with continuo~ data traffic in filll duplex L~l both directions.
From US-A-4,712,210, there i~ known a traI18Illi8~iOI1 8y~3t8Dl using bidirectional transmis~ion ill a two-lead colmec~ion.
However, thi~ i~ a so-called hal~-duple~ tem, m~ that transmi~ion is made only in one direction at a ~ime. The present invention, however, envisage~ ple~ trans sion over a two lead connection. ~e term "filll duplex" ofl;e~ carrie~
the mere meaning of a po~ibili~ to tran~mit data s~multaneou~ly ~ opposite dir~tion. The pre~sllt ~ventioIl~
howeYer, iq an example of a filll duple~ 3y8tem in the broadeist sense in that tran8m~3ion and reception of data over the two lead connection are not tied to each other, and allowing different bit rateg in the two direction~.
~v ~ D u - - . .......... .. ....
.. ..
-", - . : , .. :.. , . .. ,-:
:; .: ., ,. .. , , ;
.
aC~3m~?Elt ;~ee~ 3a ~ 4~97 The invention will be described in more detail below with refierence to the accompanying drawings, where Figure 1 shows schematically a first embodiment of a data network according to the invention, Figure 2 shows schematically a se(ond embodirnent of a data network according to the invention, Figures 3A-3C ~how in detail embodimerlts of ~arious compo-... ~ . .. . , . , . . - , .
-. . . - . . .
. , , . . - ;, . , . -. . . . . .. . . .
: . , , . . . . . .
WO~0/097l2 l'CI/~El~0/00076 q 2~fl6~9~
ponents in ~he network in Figure 2, Figure 4 show~ another embodimen~ to replace a circuit ~hown in Figure ~B and partly in Figure 3C, and Figure 5 shows schematically a third embodiment of ~he data n*twork according to the invention.
Figure l ~how6 schematically a general applîcation for ne~work link~d with full duplex through a twin lead L. A
first computer unit Dl is linked via a first adapter Al to the twin lead. A second computer unit D2 i~ linked via a eecond adapter A2 to the twin lead. Preferably, the two adapters are constructed a~ shown in Figure 3A. Both computer unit6 Dl and D2 are transmi~ting and receiving data theough the lead L. In both transmission directions, the ~ignal is a base band signal. The bafie band ~ignals can be coded identically with the same number of bits per ~econd, but ~his i~ not entirely neces6ary.
In the very schematically shown embodiment of a network configuration according to the inven~ion shown in Fi~-ure 2, a central cable concentrator l' comprises a ring network with an outlet with a media access unit (MAU) comprising a relay R for each peripheral unit PE linked to ~he syfitem. A more detailed description of a media access unit will be provided below. According to the invention, r the twin pair cable normally used in such Token Rin~systems is replaced by a twin lead cable or more suitably a ~ingle wire coaxial cable 2, e.g. RG 62, which cable i5 connected a~ its both end~ to adapters APE and AMAU, respactively.
The existing cosxial cables are thu~ utilized. Since the ~oken ~ing sy~tem work~ at a transmis~ion speed of 4 MBi~s/second or 16 ~ s/second, ~or example, a coaxial cable i~ required at least for lon~er di6tances.
::. ~ , ~ ': : . :: ~. , . .
W09()/()97l~ pcr/sEso/ooo76 2~ 9'7 Sin~e the traffic in ~o-called ba~e band tr~n~mis6ion, e.v. with the data traffic coded in so-called Manchester--code (DFM), in the Token Ring hetween the cable con-centraCor and the peripheral units goes in both directions S ~imultaneou~ly, i.e. the traffic in the cable is tran6-mitted full duplex, the coaxial connections mu6t be able to handle this. Furthermore, one must trans~r the direct current from the peripheral unit PE, which control6 the relay R in the cable concentrator.
Thi6 can be done by connecting a relatively simple adapter ~ at either end of the coaxial cable. The adapter contains a ~o-called hybride coupling, i.e. a coupling which ~epa-rate~ the tran6mis6ion data and the receiving data ~rom ~,' 15 each other, and electronic components which tran~mit the direct current without affecting the data signal.
Each adapter APE, ~MAU has a transmission buffer, a re-ceiver buffer and a transmis6ion bridge, which prevent~
20 the transmi6sion signal from the adapter from affecting its own receiver.
The adapter card ~PE (Figure 3A) iB connected at the end facing the peripheral unit PE to the in~erface which norm-25 ally feed~ a quadruple lead cable, nodes A, B, G, and H.
J TS and TM are tranæformers with a trans~ormation ~atio which can be Z:l, one for 6ending and one for receiving. A
driving voltage o~ 5 V is often available from an outlet on the peripheral uni~ PE and this can then be used to 30 drive units in the adapter, ssch as amplifiers. There can also be a certain difference between the driving voltage to a signal tran~mitting element and the ~ignal level, and therefore it can be suitable to occasion211y reduce the signal level inside the adapter APE, which occurs at the 35 tran~formation ratio 2~ higher driving voltage i3 available, the ratios of the transformer6 TS and T~ can be :: . ,: . :: : : :, :- . . :; ........... ... :
:, : . ~ . :: ' ~ ' . ' : ' ' ' : -: , W090/097l ? ~cr/S~90/0007~) ~46~97 di~f~r~nt, e.g. ~ he serie~ data signal i~ tr~nsmitted with ~o-called diferential Manchester-code (DFM), which mean~ that ~he ~ignal has no direct current component, and thu6 the signal can be transmitted via the tran~formee~
without di~tortion. The tran~mitter of the peripheral unit send~ out the fiignal in the form of a square wave with a voltage range of ~ 5 V between the node6 A and B. The ~ignal is fed from ~he adapter APE via the coaxial cable KOAX to the adapter AMAU (Figure 3B) and reaches the media acces~ uni~ MAU (Figuee 3C) at node~ C and D and i8 tran~-mitted via the tran6former TR1 in the media acce~a unit MAU to the ring. The tran~form~r TRl i6 coupled to the ' ring by relay contacts RSl and RS3 in a manner which will ! be described in more detail below.
'~;
The signal comes from the ring via rel~y contact~ RMl and R~3 to a tran~former TR2 in the media access unit MAU, which tran6former feeds the signal to the nodeR E and F on the ~e~eiv~ng pair of lead6. When the ~ignal reaches, thereaf~er, the peripheral unit PE at the nodes G and ~, -it i~ at~enuated. The attenuation i6 dependent on the total cable length from the preceding transmitter which i6 coupled into the ring.
In the adapter APE (Figure 3A) a low ohmic re6istance Rt i~ coupled ~o load the transmitter outlet from the peei-pheral unit PE with a load which i8 equivalent to ehe - normally connected pair of lead6. The normal line impe-dance for IBM~6 Token Ring i8 150 ohm, and for such a use range the Rt~ i5 Buitably 150 ohm. The two buffers 1 and aee amplifier~ with the voltage amplification 1. Tha in-put~ are hiqh-ohmic and the output6 are low-ohmic.
TB i6 a balanc:ing ~r3ns0rmer with a ratio 1:1 ant a central outlet on the peimary side. One end of the ~econd-ary side i~ d~coupled to O V via a capacitor Ca. The other end feeds the coaxial cable XOAX.
. ::~ . ;, .. , , - .
WO90/0971~ I'CT/SE90/00076 7 ~(~4~
A c~ntral outl~t ~n the transmitter tran~ormer TS i~
coupled to the signally decoupled end of ~he 6econdary ~ide of the balancing tran~former TB.
What is essential with the buf~ers l and Z in this context is that the buffer 1 has an outlet which i6 as low-ohmi~
as possible in order to load the inlet side of the ba-lancing trans~ormer TB as much as po~sible and that the buffer 2 has an outlet which is as high-ohmic as pos~lble to load the outlet side for signals as lit~le as pos~ible.
The properties of the buffers l and 2 at the end which faces the peripheral unit PE are of less importance and can therefore be selected more freely.
.
The adapter AMAU at the concentrator has an analogous con6truction to the adapter APE.
The adapter card AMAU tFigure 3B) is connected at the MAU
end to the interface, which normally feeds the four lead cable with nodes C, D, E, and F. TS' and TM' are trans-former6 with a ratio of 2:1, one for eransmitting and one for receiving. A low-ohmic re6istance Rt~ of for example l5O ohms loads the receiving signal from the media acces~
; unit ~AU with a load which is equivalent to the ~ormally connected pair of lead6.
The ~wo Duîîer~ 3 and 4 are ampliîie~6 wi~h voltage amplification l. The inlet6 are high-ohmic and the outlet6 are low-ohmic. The same dificus6ion as above regarding the input-output ohmic state of the buffer6 l and 2 i~ due also for the buffers 3 and ~, since the adapters APE and ~MAU shown in Figures 3A and 3B have the 6ame design.
; TB ' is a balan~ing tran6~0rmer with ratio l:l and with a central outlet on the primary side ~facing the MAU). One end of the secondary ~ide is decoupled to O V via a capa-- . ` . : : - : .~ ~: : : :
~VO 90/()971~ pcr/sEso/~ o76 E~
Z~ 7 citor Ca~. The other end feeds the coaxial cable KOAX.
~he siqnal decoupled iide of the balancing trans~ormee T~' i~ coupled to the central outlet of th~ tran~imitter tranG-former TS~. The cen~ral lead of the coaxial cable KOAX,which i6 connected ~o the iecondary winding6 of ~he ba-lancing tran~iformer6 TB, T~, will have a direct current potential which is determined b~y the control logic in the peripheral unit PE, which is, for example, a personal com-puter (PC).
fThe direct current ~o the relay uni~ R flows from the peripheral unit's PE control logic to the central outlet of the transmitting transformer TS in the adapter APE on 15 the primary ~iide, and then flow6 through the secondary ~.
winding of the balancing transformer TB out to the central conductor of the coaxial cable ~OAX.
In the adapter AMAU on the cable concentrator ~iide, direct current flows from the cable KOAX through the winding on the cable.~ide in the balancing transformer TB', to the central outlet on the 6econdary side of the transmitting tran~iformer TS~ and out to the relay coil or coil~i of the relay unit R in the MAU via nodes C and D. The relay unit R includes at least one relay having contacts connected to connect and disconnect the peripheral unit PE to the ring a~ will be de~icribed below.
The return current from the relay unit i8 transferred to the receiver transformer T~ o~ the adapeer AMAU at node~
E and F and i8 returned to potential O V at the se~tral outlet of the transformer TM~ on the cable concent~ator iide. In Figure 3B, thi6 is made via a ~aturated transi~i-; tor 5. ~he return cur~ent then flows via the coa~ial cable shield back to the adapter APE of the peripheral unit PEand via the central outlet of it6 receiver ~raniformer . : . . , ~ . , , i Wo ~/0~9712 11C1`/SE')0/()0076 L6~
t~ d ~ran~f~rm~r in PE, node~ G and ~1. The central outlet in the transformer of the peripheral unit PE return6 the current to o v.
The unit6 at the con~entrato~ preferably have a common driving voltage 6upply of voltage v. If the drive voltage V should be abRent, the driving of the relay unit R ~hould also cease. There~ore, in the return to the potential O V
at the central outlet of the transformer TM', a ~witch coupling can be in~erted comprising a switch tran~istor S
with itR collector-emitter portion coupled to the return ;. ! ~, and its ba~e coupled via a resistance 6 to the voltage V.
The transistor 5 is kept saturated a6 long as ~he voltage V exists, but if the voltage V should be removed, thé
tran6istor is blocked.
When tran~mitting data from the peripheral unit PE to the ring, the transmitter in the peripheral unit feeds via the tran6former TS the transmitter buffer l, which drive6 the balancing transformer TB. The primary side of the tran~-former T8 has a central outlet, which via a resi~ance Rb is connected to o V. The re6istance haæ the value ZO~4, whe~e ZO is the impedance of the coaxial cable ~OA~ ~for example 93 ohm), which is connected via the ~econdary winding of the transformer TB. The impedance of the co-axial cable KOAX i5 transmitted by the transformer ~B to the upper portion of the primary winding, and sin~e the ratio between the ~econdary winding and half of the pcimary winding is ~:l, the impedance ratio will be 4:l.
The tean~mitter buffer l thus feeds a load consi~ting of the over-transfor~ed coaxial impedance ~for example g3/4=23.25 ohm~ in ~erieR with the resi~tance Rb, which also ha6 the same value (Z3.35 ohm).
The output voltage from the buffer l will thus be divided : : . , . : -. : : . .
: . , :-.
: ~ , ~: . .
W090/09~lZ pcr/~sE~)o/~oo76 2(~4~9~ `
up i~o two equal portion~, one portion via the ee6i~tance Rb ~nd one portion via the upper half of the peimary wind-ing o~ the tran~former TB. The lower half of the primary winding receives the same voltage and polarity a~ the upper half, i.e. the ~ame voltage a~ via the resi~tance Rh. since the re~i6tance and the lower half are connected at one Doint and have the ~am~ voltage~ the voltage into the receiver buffer 2 will be O V, i.e. ~he transformer coupling ~ees to it that the signal emitted i~ nst fed to the receiver.
The voltage out of the coaxial cable KO~X will be twice that via the half primary winding, i.e. equal to the ~ignal from the transmitter buffer l.
A received ~ignal from the coaxial cable KOAX iB fed via the transformer TB to the receiver bu~er Z. That portion of the transformer TB which i~ connected to the trans-mitter buffer l, i5 ignal grounded, since the outlet of the tran~mitter buffer 1 i6 low-ohmic. The sighal into the receiver buffer 2 will be a~ large as the signal ~rom the coaxial cable KOAX.
The resi~tance Rb loads the tran6former TB at the central outlet, and the impedance 6een from the coaxial cable will be Rbx4, which i8 equal to ZO.
- The ~uppres~ion of one of the tran~mitted ~ignals ~o the re¢eiver l in the adapter APE i~ no~ total, due to toler-ances in the resi~tance Rb, tolerances in ZO in ~he ~o-axial cable, contact faults, random capacitances and ~he fact that ehe tran~former TB i~ no~ ideal.
~he residual tran~mitter signal will be added to the eig-nal received from the coaxial cable KOAX, and the receiver in the peripheLal unit PE will have thl~ error i~ the form of a time jitter. `, l .. . .. . . ... ~ . . . .... .
WO ~OtO~7]' PCr/SF,90~û00~6 ~he rati~ betwe~n Che u~e~ul ~ignal from the media acce~s unit MAU in the cable concentrator and the error ~ignal will determine how great the jitter will be.
Figure 3C show~ a common form of a media accee~ unit M~U
with the relay contacts of the relay unit R and coupled to the ring. The relay unit R ha~ two way contact~ RSl, RS3, RMl, RM3, and break contacte RS2, RSq, RM2, RM4. The Figure 3C 6hows the contacts in the position they assume when the peripheral uni~ PE i6 coupled into the ring, and thue the relay unit R is activatad. Data i~ then sent from the tran~mitting lead6 c and D in the adapter AMAU in the quadruple cable C, D, E, F, via the relay contacts RSl and RS3, respectively, out to the conductor pair Tl, T2, and data from the conductor pair T~, T4 iB received by the receiver conductors E and F via the contacts RMl and RM3, respectively. When the peripheral uni~ PE disconnect~
itself from the ring, i.e. its direct current supply to the relay R cease6 so that ie iB inac~ivated, the relay contac~s shown in Figure 3C are moved to the left. The ring i6 clo6ed by the conductor T5 being coupled to the conductor T3 via the contact RM2 and to the lead Tl via the contact RS2 and by the fact that the conductor T6 iB
coupled to the conductor T4 via the contact RM~ and to the conductor T2 via the contact RS4. Preferably, there are thus two contacte on each of the conductors T5 and T6. The secondary side of the tran~former TRl i6 coupled to the primary ~ide of the transformer TRZ via the two conductors T7 and T~ with contacts RSl, R~l and R~3, RM3.
As mentioned above, Figure 3C ~hows a commercially avail-able media acce~s unit MAU. Figure 3B thus shG~ an adapt-er AMAU, which is adapted to be coupled to thi~ com~on MAU. Figure 4 shows a circuit with a combitlation of an adapter AMAU and the portion of the media accee~ unit ~AU
in Figure 3C which lie~ to the left of the dashed line K. ~ -- ,.,...................... ~' , , : ' ' ' WO90/09712 I'~l/SE'~0/00076 12 ~4~
components corresponding to those in Figure 3C have been given the ~ame reference ~ymbols. What distigui6hes the circuit in Figure ~ from the circuit in Figure 3B together with the left-hand portion of the circui~ in Figure 3C iB
that the outle~ of the buffer 3 i~ coupled to the primary ~ide of a tran~former TSK, the secondary side of which i~
coupled to the respective contacts RS1 and ~S3 in ~he ring (~e~ Figure 3C). Furthermore, the inlet to the buffer q iB
coupled to the ~econdary side of a transformer T~K, the primary ~ide of which i8 coupled to the re~pective con-tacts RMl and RM~ in the ring. The relay coil or relay coil~ of the relay unit R~, which has contacts RSl, RSZ, RS3, RS~ and RM1, RM2, RM3, RM4, i~/are coupled between the end of the 3econdary 6ide of the tran~former TB', which end i6 decoupled to the condensor Ca' and O-potential. The relay unit R' (as well a~ the unit R in Figure 3C) controls many contacts and therefo~e can ~omprise a plurality of relay~. i.e. two. The adapter AMAUCoMB in Figure 4 thus has ~ub~tantially the same configuration as ~he adapter AMAU in Figure ~B except for the ralay unit and could be used when there iB no standard mul~i acce~s units already provided with tran~forme~6 T~l and TR2 in order to save extra transformer6 and lead connections. Thu6 in this case, ~he multi acce~ unit lacks the part on the left of the dashed line K.
- The concept of the invention i8 al80 very applicable to transmi~ion over a certain di~tance with time mul~iplex-ing at bo~h end~, for example. One advantage of the inven-tion is that for t~an~mittion via the cable, it iB not nece~6ary to coordinate the time multiplexing units on either side of the cable wi~h each other. Transmis~isn and reception of data over the two lead connection are not tied to each other.
Figure 5 ~hows an embodiment with digital time division : . , . . : ~
, . . .
- , ~ , ~ . . : . . :, , wo9r)/~)()7l P~r/SE90/00076 13 ~6~'7 multlplexor~ T~ML and T~M2 on elther ~ide of a twin lead L2, coupled thereto via an adapter of the type ~hown in Figure 3A. compute~ units a-d are coupled to the multi-plexor TDMl. Computer unit~ a~-d' are coupled to the S multiplexor TDMZ. The units a and a' communicate by half duplex, as do the unit6 b-b', c--c~, d-d'. As shown with the areows between the units and the multiplexors, the unit a receives at the same time a~ the unit b tran~mit~
and unit c transmits at the same time as unit d receives.
Thus, signal6 at t~le four connections with time multipl~x can be transferred with base band transmission to a connection working with full duplex.
While the in~ention ha6 been illu~trated and de6cribed above in connection with certain embodiment6 thereof, it ~hould be under6tood that a number of changes, modifica-tion6 and substitutions therein will readily occur to one ~killed in the art without departing from the ~cope and spirit of the invention.
., ~ .
-: ~ , :: ~ , ,
Office data ~roce~6ing sy6tem~ often involve expensive cable inseallation between a central computer and a number of terminals, callad peripheral units below. Different type~ of data processing ~ystems require different types -, of cables. A change in data processing ~ystem o~en requires re-laying the cables with the accompanying cost thereof.
~_' There are star networks, in which all ~he peripheral units are connec~ed to a central uni~ by individual cables. If some fault arises in a peripheral unit, the other peri-pheral units in the system are not affected. Connecting anew peripheral unit i8 done simply by connecting an addi-tional cable to the central unit.
one disadvantage of this peripheral system is ~hat the 23 flow of data between the various peripheral units i8 adminis~ered by the central unit, which decrea~es the effectiveness of the system if data is to be sent b~tween -J the various peripheral units. Another disadvantage i8 $hat expansion with numerous peripheral uni~s requires numerouE
- 25 ports in the central unit, making it expensive. Further- ::
more, there iB a limit to what the cen~ral unit can administer.
one example of a star network i8 the IBM 3270 system, which use~ an RG 62 coaxial cable between the ~entral unit ;. and the peripheral unit. Transmis6ion is half duplex. The SS 3 network in Alfaskop( ) is a staE network which normally uses æhielded double lead but which can also use RG 6Z coaxial cable.
: . ,,~ .. . , . , :
- , : ~ ,. . : . : :~ : .
.. ~ . . : . . . . .. : . . .. : :
: . . . .. . . . :. ~ . - - :
: ~ ~ .: . . : .
woso/os7l2 PC~/SE')IJ/00076 2 21)46~9'7 ~h~r~ ar~ ~rl~ coupled rinq networks which have the advantaqe that the flow of data in the ring pa~e~ all the peripheral units without any controlling central unit. The di~advantage6 are that a 6eries linked ring i6 difficult to expand or change and it is le6s reliable. Since all the peripheral unit~ are connected in serie~ in the ring, addition o~ another peripheral unit requires new cable6 between the units. Removal of a peripheral unit from the ring i~ al60 difficult, ~ince the ring mu~t be broken.
Since there iB no central point where the cables converge, problem~ can spread throughout the entire ring. A ~imple two conductor cable or a coaxial cable can be usad, ~ince the flow of dat~ iB alway6 in the 6ame direction in the ring, i.e. the tran6mi66ion i8 BimpleX.
There are also staL linked ring network6, which re~ain the advantage of serie6 link data flow between the peripheral unit6 but avoid ~ome of the di~advantages of the aeries linked network.
In a ~ta~ linked network, there i~ a cable for each peripheral unit ~o a central point, where a ~o-called cable concentrator is located. The cable concen~rator contains only media acces6 units with relay6 and relay contacts with a relay for each cable. The relay can connect the cable to the ring on order from the peripheral unit and i~ a fault ari6e~ it can disconnect the cable from the ring. If the cable i~ ronnected, it i~ thu~ a portion of the ring, and thi3 require~ a cable with two pairs of conductors. The eran~mis~ion through the ~able is full duplex. When the cable iB di~connected, the ring i~
rerouted internally in the cable concentrator.
one example of thi~ type of network i~ the ~o-called Token Ring, which use6 a shielded twin lead between the cable concentrator and the peripheral unit6.
.
.~
: :-- , .
Replace~lellt ~heet 3 2046~97 If a user, who presently has a star net~vork installed, for ex~mple a 3270 system, wishes to install a Token Ring ~ystem, all of the cables must be replaced with a twin cable, e.g. of I:BM
type. This i9 of~en quite expen~ive and time con~uming, especiaIly in buildiIIgs not pro~ded ~nth space for cable~.
If it were possible to use the e2~st~g cables, this would be a great advantage. Since the Token Ring system operates ~t a trnasmission speed of 4 Mbits/~econLd or 16 Mbita/~econd, this requires a coa~;ial cable, at lea~t for longer distauce~.
e~io~ dec ~o pro~iae a system where exist~ng installed cables for a ~tar ~etwor~, e.g. ~hielded tWill lead cable or coagial cable with single conductor~, can be u~ed in installing a data proCeSSiDg system requinng a cable with at le~t two pairs of lead~.
The abovemen~ioned purpose ~ achieved according ~o the inventio~ w~th an arrangement having the characteri~ic~
disclosed ~ cla~m1. Further ~eatures and deve30pments ~re disdosed in the subclaims.
The invention is, however, applicable to a~y type of point-to-poi~t comlection between two unit~ with baae band 2 5 tran~ rnis~ion with continuo~ data traffic in filll duplex L~l both directions.
From US-A-4,712,210, there i~ known a traI18Illi8~iOI1 8y~3t8Dl using bidirectional transmis~ion ill a two-lead colmec~ion.
However, thi~ i~ a so-called hal~-duple~ tem, m~ that transmi~ion is made only in one direction at a ~ime. The present invention, however, envisage~ ple~ trans sion over a two lead connection. ~e term "filll duplex" ofl;e~ carrie~
the mere meaning of a po~ibili~ to tran~mit data s~multaneou~ly ~ opposite dir~tion. The pre~sllt ~ventioIl~
howeYer, iq an example of a filll duple~ 3y8tem in the broadeist sense in that tran8m~3ion and reception of data over the two lead connection are not tied to each other, and allowing different bit rateg in the two direction~.
~v ~ D u - - . .......... .. ....
.. ..
-", - . : , .. :.. , . .. ,-:
:; .: ., ,. .. , , ;
.
aC~3m~?Elt ;~ee~ 3a ~ 4~97 The invention will be described in more detail below with refierence to the accompanying drawings, where Figure 1 shows schematically a first embodiment of a data network according to the invention, Figure 2 shows schematically a se(ond embodirnent of a data network according to the invention, Figures 3A-3C ~how in detail embodimerlts of ~arious compo-... ~ . .. . , . , . . - , .
-. . . - . . .
. , , . . - ;, . , . -. . . . . .. . . .
: . , , . . . . . .
WO~0/097l2 l'CI/~El~0/00076 q 2~fl6~9~
ponents in ~he network in Figure 2, Figure 4 show~ another embodimen~ to replace a circuit ~hown in Figure ~B and partly in Figure 3C, and Figure 5 shows schematically a third embodiment of ~he data n*twork according to the invention.
Figure l ~how6 schematically a general applîcation for ne~work link~d with full duplex through a twin lead L. A
first computer unit Dl is linked via a first adapter Al to the twin lead. A second computer unit D2 i~ linked via a eecond adapter A2 to the twin lead. Preferably, the two adapters are constructed a~ shown in Figure 3A. Both computer unit6 Dl and D2 are transmi~ting and receiving data theough the lead L. In both transmission directions, the ~ignal is a base band signal. The bafie band ~ignals can be coded identically with the same number of bits per ~econd, but ~his i~ not entirely neces6ary.
In the very schematically shown embodiment of a network configuration according to the inven~ion shown in Fi~-ure 2, a central cable concentrator l' comprises a ring network with an outlet with a media access unit (MAU) comprising a relay R for each peripheral unit PE linked to ~he syfitem. A more detailed description of a media access unit will be provided below. According to the invention, r the twin pair cable normally used in such Token Rin~systems is replaced by a twin lead cable or more suitably a ~ingle wire coaxial cable 2, e.g. RG 62, which cable i5 connected a~ its both end~ to adapters APE and AMAU, respactively.
The existing cosxial cables are thu~ utilized. Since the ~oken ~ing sy~tem work~ at a transmis~ion speed of 4 MBi~s/second or 16 ~ s/second, ~or example, a coaxial cable i~ required at least for lon~er di6tances.
::. ~ , ~ ': : . :: ~. , . .
W09()/()97l~ pcr/sEso/ooo76 2~ 9'7 Sin~e the traffic in ~o-called ba~e band tr~n~mis6ion, e.v. with the data traffic coded in so-called Manchester--code (DFM), in the Token Ring hetween the cable con-centraCor and the peripheral units goes in both directions S ~imultaneou~ly, i.e. the traffic in the cable is tran6-mitted full duplex, the coaxial connections mu6t be able to handle this. Furthermore, one must trans~r the direct current from the peripheral unit PE, which control6 the relay R in the cable concentrator.
Thi6 can be done by connecting a relatively simple adapter ~ at either end of the coaxial cable. The adapter contains a ~o-called hybride coupling, i.e. a coupling which ~epa-rate~ the tran6mis6ion data and the receiving data ~rom ~,' 15 each other, and electronic components which tran~mit the direct current without affecting the data signal.
Each adapter APE, ~MAU has a transmission buffer, a re-ceiver buffer and a transmis6ion bridge, which prevent~
20 the transmi6sion signal from the adapter from affecting its own receiver.
The adapter card ~PE (Figure 3A) iB connected at the end facing the peripheral unit PE to the in~erface which norm-25 ally feed~ a quadruple lead cable, nodes A, B, G, and H.
J TS and TM are tranæformers with a trans~ormation ~atio which can be Z:l, one for 6ending and one for receiving. A
driving voltage o~ 5 V is often available from an outlet on the peripheral uni~ PE and this can then be used to 30 drive units in the adapter, ssch as amplifiers. There can also be a certain difference between the driving voltage to a signal tran~mitting element and the ~ignal level, and therefore it can be suitable to occasion211y reduce the signal level inside the adapter APE, which occurs at the 35 tran~formation ratio 2~ higher driving voltage i3 available, the ratios of the transformer6 TS and T~ can be :: . ,: . :: : : :, :- . . :; ........... ... :
:, : . ~ . :: ' ~ ' . ' : ' ' ' : -: , W090/097l ? ~cr/S~90/0007~) ~46~97 di~f~r~nt, e.g. ~ he serie~ data signal i~ tr~nsmitted with ~o-called diferential Manchester-code (DFM), which mean~ that ~he ~ignal has no direct current component, and thu6 the signal can be transmitted via the tran~formee~
without di~tortion. The tran~mitter of the peripheral unit send~ out the fiignal in the form of a square wave with a voltage range of ~ 5 V between the node6 A and B. The ~ignal is fed from ~he adapter APE via the coaxial cable KOAX to the adapter AMAU (Figure 3B) and reaches the media acces~ uni~ MAU (Figuee 3C) at node~ C and D and i8 tran~-mitted via the tran6former TR1 in the media acce~a unit MAU to the ring. The tran~form~r TRl i6 coupled to the ' ring by relay contacts RSl and RS3 in a manner which will ! be described in more detail below.
'~;
The signal comes from the ring via rel~y contact~ RMl and R~3 to a tran~former TR2 in the media access unit MAU, which tran6former feeds the signal to the nodeR E and F on the ~e~eiv~ng pair of lead6. When the ~ignal reaches, thereaf~er, the peripheral unit PE at the nodes G and ~, -it i~ at~enuated. The attenuation i6 dependent on the total cable length from the preceding transmitter which i6 coupled into the ring.
In the adapter APE (Figure 3A) a low ohmic re6istance Rt i~ coupled ~o load the transmitter outlet from the peei-pheral unit PE with a load which i8 equivalent to ehe - normally connected pair of lead6. The normal line impe-dance for IBM~6 Token Ring i8 150 ohm, and for such a use range the Rt~ i5 Buitably 150 ohm. The two buffers 1 and aee amplifier~ with the voltage amplification 1. Tha in-put~ are hiqh-ohmic and the output6 are low-ohmic.
TB i6 a balanc:ing ~r3ns0rmer with a ratio 1:1 ant a central outlet on the peimary side. One end of the ~econd-ary side i~ d~coupled to O V via a capacitor Ca. The other end feeds the coaxial cable XOAX.
. ::~ . ;, .. , , - .
WO90/0971~ I'CT/SE90/00076 7 ~(~4~
A c~ntral outl~t ~n the transmitter tran~ormer TS i~
coupled to the signally decoupled end of ~he 6econdary ~ide of the balancing tran~former TB.
What is essential with the buf~ers l and Z in this context is that the buffer 1 has an outlet which i6 as low-ohmi~
as possible in order to load the inlet side of the ba-lancing trans~ormer TB as much as po~sible and that the buffer 2 has an outlet which is as high-ohmic as pos~lble to load the outlet side for signals as lit~le as pos~ible.
The properties of the buffers l and 2 at the end which faces the peripheral unit PE are of less importance and can therefore be selected more freely.
.
The adapter AMAU at the concentrator has an analogous con6truction to the adapter APE.
The adapter card AMAU tFigure 3B) is connected at the MAU
end to the interface, which normally feeds the four lead cable with nodes C, D, E, and F. TS' and TM' are trans-former6 with a ratio of 2:1, one for eransmitting and one for receiving. A low-ohmic re6istance Rt~ of for example l5O ohms loads the receiving signal from the media acces~
; unit ~AU with a load which is equivalent to the ~ormally connected pair of lead6.
The ~wo Duîîer~ 3 and 4 are ampliîie~6 wi~h voltage amplification l. The inlet6 are high-ohmic and the outlet6 are low-ohmic. The same dificus6ion as above regarding the input-output ohmic state of the buffer6 l and 2 i~ due also for the buffers 3 and ~, since the adapters APE and ~MAU shown in Figures 3A and 3B have the 6ame design.
; TB ' is a balan~ing tran6~0rmer with ratio l:l and with a central outlet on the primary side ~facing the MAU). One end of the secondary ~ide is decoupled to O V via a capa-- . ` . : : - : .~ ~: : : :
~VO 90/()971~ pcr/sEso/~ o76 E~
Z~ 7 citor Ca~. The other end feeds the coaxial cable KOAX.
~he siqnal decoupled iide of the balancing trans~ormee T~' i~ coupled to the central outlet of th~ tran~imitter tranG-former TS~. The cen~ral lead of the coaxial cable KOAX,which i6 connected ~o the iecondary winding6 of ~he ba-lancing tran~iformer6 TB, T~, will have a direct current potential which is determined b~y the control logic in the peripheral unit PE, which is, for example, a personal com-puter (PC).
fThe direct current ~o the relay uni~ R flows from the peripheral unit's PE control logic to the central outlet of the transmitting transformer TS in the adapter APE on 15 the primary ~iide, and then flow6 through the secondary ~.
winding of the balancing transformer TB out to the central conductor of the coaxial cable ~OAX.
In the adapter AMAU on the cable concentrator ~iide, direct current flows from the cable KOAX through the winding on the cable.~ide in the balancing transformer TB', to the central outlet on the 6econdary side of the transmitting tran~iformer TS~ and out to the relay coil or coil~i of the relay unit R in the MAU via nodes C and D. The relay unit R includes at least one relay having contacts connected to connect and disconnect the peripheral unit PE to the ring a~ will be de~icribed below.
The return current from the relay unit i8 transferred to the receiver transformer T~ o~ the adapeer AMAU at node~
E and F and i8 returned to potential O V at the se~tral outlet of the transformer TM~ on the cable concent~ator iide. In Figure 3B, thi6 is made via a ~aturated transi~i-; tor 5. ~he return cur~ent then flows via the coa~ial cable shield back to the adapter APE of the peripheral unit PEand via the central outlet of it6 receiver ~raniformer . : . . , ~ . , , i Wo ~/0~9712 11C1`/SE')0/()0076 L6~
t~ d ~ran~f~rm~r in PE, node~ G and ~1. The central outlet in the transformer of the peripheral unit PE return6 the current to o v.
The unit6 at the con~entrato~ preferably have a common driving voltage 6upply of voltage v. If the drive voltage V should be abRent, the driving of the relay unit R ~hould also cease. There~ore, in the return to the potential O V
at the central outlet of the transformer TM', a ~witch coupling can be in~erted comprising a switch tran~istor S
with itR collector-emitter portion coupled to the return ;. ! ~, and its ba~e coupled via a resistance 6 to the voltage V.
The transistor 5 is kept saturated a6 long as ~he voltage V exists, but if the voltage V should be removed, thé
tran6istor is blocked.
When tran~mitting data from the peripheral unit PE to the ring, the transmitter in the peripheral unit feeds via the tran6former TS the transmitter buffer l, which drive6 the balancing transformer TB. The primary side of the tran~-former T8 has a central outlet, which via a resi~ance Rb is connected to o V. The re6istance haæ the value ZO~4, whe~e ZO is the impedance of the coaxial cable ~OA~ ~for example 93 ohm), which is connected via the ~econdary winding of the transformer TB. The impedance of the co-axial cable KOAX i5 transmitted by the transformer ~B to the upper portion of the primary winding, and sin~e the ratio between the ~econdary winding and half of the pcimary winding is ~:l, the impedance ratio will be 4:l.
The tean~mitter buffer l thus feeds a load consi~ting of the over-transfor~ed coaxial impedance ~for example g3/4=23.25 ohm~ in ~erieR with the resi~tance Rb, which also ha6 the same value (Z3.35 ohm).
The output voltage from the buffer l will thus be divided : : . , . : -. : : . .
: . , :-.
: ~ , ~: . .
W090/09~lZ pcr/~sE~)o/~oo76 2(~4~9~ `
up i~o two equal portion~, one portion via the ee6i~tance Rb ~nd one portion via the upper half of the peimary wind-ing o~ the tran~former TB. The lower half of the primary winding receives the same voltage and polarity a~ the upper half, i.e. the ~ame voltage a~ via the resi~tance Rh. since the re~i6tance and the lower half are connected at one Doint and have the ~am~ voltage~ the voltage into the receiver buffer 2 will be O V, i.e. ~he transformer coupling ~ees to it that the signal emitted i~ nst fed to the receiver.
The voltage out of the coaxial cable KO~X will be twice that via the half primary winding, i.e. equal to the ~ignal from the transmitter buffer l.
A received ~ignal from the coaxial cable KOAX iB fed via the transformer TB to the receiver bu~er Z. That portion of the transformer TB which i~ connected to the trans-mitter buffer l, i5 ignal grounded, since the outlet of the tran~mitter buffer 1 i6 low-ohmic. The sighal into the receiver buffer 2 will be a~ large as the signal ~rom the coaxial cable KOAX.
The resi~tance Rb loads the tran6former TB at the central outlet, and the impedance 6een from the coaxial cable will be Rbx4, which i8 equal to ZO.
- The ~uppres~ion of one of the tran~mitted ~ignals ~o the re¢eiver l in the adapter APE i~ no~ total, due to toler-ances in the resi~tance Rb, tolerances in ZO in ~he ~o-axial cable, contact faults, random capacitances and ~he fact that ehe tran~former TB i~ no~ ideal.
~he residual tran~mitter signal will be added to the eig-nal received from the coaxial cable KOAX, and the receiver in the peripheLal unit PE will have thl~ error i~ the form of a time jitter. `, l .. . .. . . ... ~ . . . .... .
WO ~OtO~7]' PCr/SF,90~û00~6 ~he rati~ betwe~n Che u~e~ul ~ignal from the media acce~s unit MAU in the cable concentrator and the error ~ignal will determine how great the jitter will be.
Figure 3C show~ a common form of a media accee~ unit M~U
with the relay contacts of the relay unit R and coupled to the ring. The relay unit R ha~ two way contact~ RSl, RS3, RMl, RM3, and break contacte RS2, RSq, RM2, RM4. The Figure 3C 6hows the contacts in the position they assume when the peripheral uni~ PE i6 coupled into the ring, and thue the relay unit R is activatad. Data i~ then sent from the tran~mitting lead6 c and D in the adapter AMAU in the quadruple cable C, D, E, F, via the relay contacts RSl and RS3, respectively, out to the conductor pair Tl, T2, and data from the conductor pair T~, T4 iB received by the receiver conductors E and F via the contacts RMl and RM3, respectively. When the peripheral uni~ PE disconnect~
itself from the ring, i.e. its direct current supply to the relay R cease6 so that ie iB inac~ivated, the relay contac~s shown in Figure 3C are moved to the left. The ring i6 clo6ed by the conductor T5 being coupled to the conductor T3 via the contact RM2 and to the lead Tl via the contact RS2 and by the fact that the conductor T6 iB
coupled to the conductor T4 via the contact RM~ and to the conductor T2 via the contact RS4. Preferably, there are thus two contacte on each of the conductors T5 and T6. The secondary side of the tran~former TRl i6 coupled to the primary ~ide of the transformer TRZ via the two conductors T7 and T~ with contacts RSl, R~l and R~3, RM3.
As mentioned above, Figure 3C ~hows a commercially avail-able media acce~s unit MAU. Figure 3B thus shG~ an adapt-er AMAU, which is adapted to be coupled to thi~ com~on MAU. Figure 4 shows a circuit with a combitlation of an adapter AMAU and the portion of the media accee~ unit ~AU
in Figure 3C which lie~ to the left of the dashed line K. ~ -- ,.,...................... ~' , , : ' ' ' WO90/09712 I'~l/SE'~0/00076 12 ~4~
components corresponding to those in Figure 3C have been given the ~ame reference ~ymbols. What distigui6hes the circuit in Figure ~ from the circuit in Figure 3B together with the left-hand portion of the circui~ in Figure 3C iB
that the outle~ of the buffer 3 i~ coupled to the primary ~ide of a tran~former TSK, the secondary side of which i~
coupled to the respective contacts RS1 and ~S3 in ~he ring (~e~ Figure 3C). Furthermore, the inlet to the buffer q iB
coupled to the ~econdary side of a transformer T~K, the primary ~ide of which i8 coupled to the re~pective con-tacts RMl and RM~ in the ring. The relay coil or relay coil~ of the relay unit R~, which has contacts RSl, RSZ, RS3, RS~ and RM1, RM2, RM3, RM4, i~/are coupled between the end of the 3econdary 6ide of the tran~former TB', which end i6 decoupled to the condensor Ca' and O-potential. The relay unit R' (as well a~ the unit R in Figure 3C) controls many contacts and therefo~e can ~omprise a plurality of relay~. i.e. two. The adapter AMAUCoMB in Figure 4 thus has ~ub~tantially the same configuration as ~he adapter AMAU in Figure ~B except for the ralay unit and could be used when there iB no standard mul~i acce~s units already provided with tran~forme~6 T~l and TR2 in order to save extra transformer6 and lead connections. Thu6 in this case, ~he multi acce~ unit lacks the part on the left of the dashed line K.
- The concept of the invention i8 al80 very applicable to transmi~ion over a certain di~tance with time mul~iplex-ing at bo~h end~, for example. One advantage of the inven-tion is that for t~an~mittion via the cable, it iB not nece~6ary to coordinate the time multiplexing units on either side of the cable wi~h each other. Transmis~isn and reception of data over the two lead connection are not tied to each other.
Figure 5 ~hows an embodiment with digital time division : . , . . : ~
, . . .
- , ~ , ~ . . : . . :, , wo9r)/~)()7l P~r/SE90/00076 13 ~6~'7 multlplexor~ T~ML and T~M2 on elther ~ide of a twin lead L2, coupled thereto via an adapter of the type ~hown in Figure 3A. compute~ units a-d are coupled to the multi-plexor TDMl. Computer unit~ a~-d' are coupled to the S multiplexor TDMZ. The units a and a' communicate by half duplex, as do the unit6 b-b', c--c~, d-d'. As shown with the areows between the units and the multiplexors, the unit a receives at the same time a~ the unit b tran~mit~
and unit c transmits at the same time as unit d receives.
Thus, signal6 at t~le four connections with time multipl~x can be transferred with base band transmission to a connection working with full duplex.
While the in~ention ha6 been illu~trated and de6cribed above in connection with certain embodiment6 thereof, it ~hould be under6tood that a number of changes, modifica-tion6 and substitutions therein will readily occur to one ~killed in the art without departing from the ~cope and spirit of the invention.
., ~ .
-: ~ , :: ~ , ,
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Network system for data transmission between at least two units (PE, MAU) with base band transmission and full duplex over a transmission channel, wherein the transmission channel comprises:
a two lead connection (L; KOAX; L1);
an adapter (A1, A2; APE, AMAU; AMAUCOMB; AT1, AT2) on either side of said two lead connection, each adapter being coupled to one of said units (D1, D2; PE, MAU; TDM1, TDM2) and having (a) a transmitting file (TS, TS') for receiving data which is to be transmitted out to said two lead connection to said other adapter, (b) a receiving file (TM, TM') for transmitting data sent from the other unit via said two lead connection to said unit to which it is coupled, and characterized by (c) sorting-out means (TB, Rb, 1, 2; TB', Rb', 3, 4) for sorting out the data from said two lead connection which said adapter does not itself send thereon, and feeding this data to said receiving file (TM, TM'), said sorting-out means being uncoordinated to said transmitting file, admitting transmitting and reception of data over the two lead connection being untied to each other.
a two lead connection (L; KOAX; L1);
an adapter (A1, A2; APE, AMAU; AMAUCOMB; AT1, AT2) on either side of said two lead connection, each adapter being coupled to one of said units (D1, D2; PE, MAU; TDM1, TDM2) and having (a) a transmitting file (TS, TS') for receiving data which is to be transmitted out to said two lead connection to said other adapter, (b) a receiving file (TM, TM') for transmitting data sent from the other unit via said two lead connection to said unit to which it is coupled, and characterized by (c) sorting-out means (TB, Rb, 1, 2; TB', Rb', 3, 4) for sorting out the data from said two lead connection which said adapter does not itself send thereon, and feeding this data to said receiving file (TM, TM'), said sorting-out means being uncoordinated to said transmitting file, admitting transmitting and reception of data over the two lead connection being untied to each other.
2. Network system according to claim 1, characterized in that in each adapter said sorting-out means comprises a transmission bridge with a balancing transformer (TB, TB') having its primary side divided into two identical portions, one of these portions being coupled to said transmitting file and the other to said receiving file, and a central outlet on the primary side coupled via a resistance (Rb, Rb') to earth.
3. Network system according to claim 2, characterized in that to said portion of the balancing transformer primary aide, which is coupled to the transmitting file, there is coupled the outlet of a first buffer circuit (1; 3) having a low-ohmic outlet, and to said portion of the balancing transformer primary side, which is coupled to the re-ceiving file, there is coupled the inlet of a second buffer circuit (2; 4) having a high-ohmic inlet.
4. Network system according to one of the preceding claims, characterized in that one of said units (MAU) is coupled as a portion of a ring network (Figures 2 and 3C).
5. Network system according to claim 4, characterized in that the ring network is in the form of a cable concentra-tor with a relay arrangement (R; R') for each connection with a peripheral unit (PE), which relay unit, controlled from the peripheral unit (PE), switches the relay arrange-ment on or off by sending a direct current signal through a coupled direct current path through both of the adapters and the two lead connection to the relay coil.
6. Network system according to one of the preceding claims, characterized in that the two lead connection is a coaxial cable.
7. Network system according to one of the preceding claims, characterized in that the transmitting file in the adapter (APE) comprises a transformer (TS) and the buffer connection (1) having a low-ohmic outlet.
8. Network system according to one of the preceding claims, characterized in that the receiving file in the adapter (APE) comprises the buffer connection (2) having a high-ohmic inlet and a transformer (TM).
9. Network system according to one of claims 1-3, 6-8, characterized in that a digital time divider multiplexer (TDM1, TDNM2) is coupled to each adapter (AT1, AT2) on either side of the two lead connection (L2).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE8900465-9 | 1989-02-10 | ||
| SE8900465A SE461367B (en) | 1989-02-10 | 1989-02-10 | POST ARRANGEMENTS FOR DATA TRANSFER |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2046297A1 true CA2046297A1 (en) | 1990-08-11 |
Family
ID=20375009
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002046297A Abandoned CA2046297A1 (en) | 1989-02-10 | 1990-02-06 | Network system for data transmission |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US5231628A (en) |
| EP (1) | EP0457820B1 (en) |
| AT (1) | ATE140352T1 (en) |
| CA (1) | CA2046297A1 (en) |
| DE (1) | DE69027766T2 (en) |
| FI (1) | FI913770A0 (en) |
| SE (1) | SE461367B (en) |
| WO (1) | WO1990009712A1 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI83007C (en) * | 1989-10-05 | 1991-05-10 | Nokia Data Systems | Digital data transfer system |
| US5680397A (en) * | 1995-03-13 | 1997-10-21 | International Business Machines Corporation | Multi-port LAN switch for a token-ring network |
| US5625621A (en) * | 1995-03-13 | 1997-04-29 | International Business Machines Corporation | Method and system of automatically configuring a LAN switch portof a multi-port LAN switch based on an attached device type |
| US6377562B1 (en) | 1997-11-18 | 2002-04-23 | Bell Atlantic Network Services, Inc. | Wireless asymmetric local loop (WASL) communication |
| US6240094B1 (en) | 1997-12-22 | 2001-05-29 | Bell Atlantic Network Services, Inc. | Statistical time division multiplexer for a wireless asymmetric local loop communication system |
| US8787571B2 (en) | 2011-10-19 | 2014-07-22 | General Electric Company | Wired communications systems with improved capacity and security |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2063475A5 (en) * | 1969-10-17 | 1971-07-09 | Labo Cent Telecommunicat | |
| US3983323A (en) * | 1973-09-24 | 1976-09-28 | Sperry Rand Corporation | Full-duplex digital transmission line system |
| US4326287A (en) * | 1980-06-30 | 1982-04-20 | International Business Machines Corp. | Two wire bi-directional digital telephone link |
| JPS60130235A (en) * | 1983-12-16 | 1985-07-11 | Fujitsu Ltd | Data and voice transmitter |
| IT1178913B (en) * | 1984-03-26 | 1987-09-16 | Cselt Centro Studi Lab Telecom | ZIONAL TWO-WIRE TRANSMISSION SYSTEM WITH D ECHO CANCELLATION |
| US4712210A (en) * | 1984-09-07 | 1987-12-08 | Lee Data Corporation | Signal conversion circuit for interconnecting coaxial cable and a twisted pair |
| JPH0616592B2 (en) * | 1985-12-23 | 1994-03-02 | 富士通株式会社 | FDM modem |
| NL8600087A (en) * | 1986-01-17 | 1987-08-17 | Philips Nv | DEVICE FOR FULL-DUPLEX DATA TRANSMISSION ON TWO-WIRE CONNECTIONS. |
-
1989
- 1989-02-10 SE SE8900465A patent/SE461367B/en not_active Application Discontinuation
-
1990
- 1990-02-06 EP EP90903239A patent/EP0457820B1/en not_active Expired - Lifetime
- 1990-02-06 DE DE69027766T patent/DE69027766T2/en not_active Expired - Fee Related
- 1990-02-06 AT AT90903239T patent/ATE140352T1/en not_active IP Right Cessation
- 1990-02-06 WO PCT/SE1990/000076 patent/WO1990009712A1/en active IP Right Grant
- 1990-02-06 CA CA002046297A patent/CA2046297A1/en not_active Abandoned
- 1990-02-08 US US07/476,683 patent/US5231628A/en not_active Expired - Fee Related
-
1991
- 1991-08-08 FI FI913770A patent/FI913770A0/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| DE69027766D1 (en) | 1996-08-14 |
| US5231628A (en) | 1993-07-27 |
| FI913770A0 (en) | 1991-08-08 |
| WO1990009712A1 (en) | 1990-08-23 |
| EP0457820B1 (en) | 1996-07-10 |
| ATE140352T1 (en) | 1996-07-15 |
| EP0457820A1 (en) | 1991-11-27 |
| SE8900465D0 (en) | 1989-02-10 |
| SE461367B (en) | 1990-02-05 |
| DE69027766T2 (en) | 1997-02-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| AU600577B2 (en) | Lan communication system and medium adapter for use therewith | |
| CA1252873A (en) | Ring packet switch | |
| US5280477A (en) | Network synchronous data distribution system | |
| CA1251844A (en) | Telecommunication system, in particular telephone system | |
| KR960705450A (en) | A LOCAL AREA NETWORK FOR SIMULTANEOUS, BI-DIRECTIONAL TRANSMISSION OF VIDEO BANDWIDTH SIGNALS | |
| GB2131254A (en) | Collision avoidance circuit for packet switched communication system | |
| JPH02308641A (en) | Method for connecting data cell stream | |
| US6026078A (en) | Apparatus and method for providing multiple network port configurations | |
| CA2046297A1 (en) | Network system for data transmission | |
| EP0833509B1 (en) | An interface for an asymmetric digital subscriber line transceiver | |
| IE54402B1 (en) | Apparatus for connecting digital terminals to a digital exchange | |
| US7106688B2 (en) | System and method for preventing phantom data communication links | |
| JPH01231539A (en) | Multi-point terminal system | |
| US3783183A (en) | Arrangement for the connecting of transmission devices to a program controlled electronic data exchange system | |
| JPH118572A (en) | Transmission line extending system | |
| US6240064B1 (en) | Ring structure 1:N duplex communication equipment and data communication method | |
| JPS6143850A (en) | Packet continuous transmission system | |
| EP0166193B1 (en) | Switch configured communication network | |
| EP0143942A2 (en) | System for exchanging data between radio base sites | |
| JP3081822B2 (en) | ATM switching equipment | |
| JPS59117846A (en) | Data communicating equipment | |
| JPH08205235A (en) | Method and device for distributing control signal load | |
| JPH0360220B2 (en) | ||
| JPH01108822A (en) | Transmission circuit for auxiliary transmission line | |
| JPS5825743A (en) | Data transmitting and receiving circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |