INTEGRATION OF INTERNET TELEPHONY GATEWAY HARDWARE
BACKGROUND OF THE INVENTION The present invention relates generally to internet telephony and more particularly to the integration of the internet telephony gateway ("ITG") into the telephony switch.
In prior art computer telephony integration systems, subscriber telephones are connected through a switching platform and an internet telephony gateway (ITG) to an Internet network. As shown in Figure 1, the Internet 10 is conventionally available to a number of different types of equipment by connection through ITGs 12, 14, 16 and 18.
By integration of the ITG 18 into the telephone switch 20, significant resources are saved and the robustness of the ITG is significantly enhanced.
Higher level of control over the conversion of IP to PCM format is available because of the integrated microprocessor control .
The flow control provided by the integration allows the switch microprocessor to utilize multiple IP connections in an efficient manner, avoiding overflowing an IP connection and distorting the encoded voice conversations. Flow control also permits the use of alternate routes when IP connections fail or are overloaded, least cost routing, and out of band DTMF detection .
Further, the problems associated with obtaining type approval of ITGs throughout the world of the Internet are significantly reduced by integration of the ITG into a telephony switch which already enjoys type approval.
It is accordingly an object of the present invention to
provide a novel integrated telephony switch and internet gateway or interface and method.
It is accordingly an object of the present invention to provide a novel method and integrated telephony switch and internet gateway or interface.
It is another object of the present invention to provide a novel method and integrated telephony switch and internet gateway which significantly reduces the number of components and thus the expense of the system.
It is yet another object of the present invention to provide a novel method and integrated telephony switch and internet gateway in which administration is provided from a single point thus reducing the real cost of system operation.
It is still another object of the present invention to provide a novel method and integrated telephony switch and internet gateway in which the robustness of the ITG is significantly enhanced.
It is yet still another object of the present invention to provide a novel method and integrated telephony switch and internet gateway in which a higher level of flow control is achieved.
These and many other objects and advantages will be readily apparent to one skilled in this art from a perusal of the claims and the following detailed description when read in conjunction with the appended drawings.
THE DRAWINGS Figure 1 is pictorial representation of the prior art internet illustrating some of the users.
Figure 2 is a pictorial representation of a portion of
Figure 1 showing a typical prior art internet telephone system.
Figure 3 is a pictorial representation of a prior art telephony switch in use in an Internet telephone system.
Figure 4 is a pictorial representation of one embodiment of the ITG of the present invention;
Figure 5 is schematic diagram representing one way of implementing the ITG of the present invention.
THE DETAILED DESCRIPTION
As shown in more detail in the prior art system of Figure 2, a telephone 22 is connected conventionally to a circuit switch 24 which in turn is connected through an ITG 26 to an IP network such as the Internet or a private LAN 28. A second telephone 30 is also connected to a circuit switch 32 and through an ITG 34 to the IP network 28. In this way, the first telephone 22 may communicate with the telephone 30 via the IP network. The references hereinafter to the Internet are intended to be generic to the Internet and to any other IP network .
With reference to the prior art system illustrated in Figure 3, a conventional telephony switch 40 includes the telephone switches 42 which receive the incoming calls and apply them through an interface circuit II to provide a Tl or other conventional telephone truck which is in turn connected to the public switched telephone network ("PSTN") 44.
The telephony switch 40 also includes a microprocessor 46 which controls the switching, signaling detection and signaling generation (trunking) of the calls in the interface II and
which also provides control signals, converted in an interface
13 to a sophisticated inter-switch signaling format such as Signaling System 7 ("SS7") for application to the Intelligent Network ("IN") 48 overlay to the PSTN.
With continued reference to Figure 3, the circuit switched Tl signal from the telephony switch is applied through an Internet Telephone Gateway ("ITG") 50 to provide one or more signals in the packet switched Internet Protocol ("IP") suitable for application to the Internet 52 overlay on the PSTN. As will readily be understood, the ITG 50 provides a Tl to IP conversion which is outside the control of the microprocessor of the telephone switch.
With reference to Figure 4 where an embodiment of the present invention is illustrated, like numerical designations are used for like elements in the prior art system of Figure 3 to facilitate an understanding of the differences therebetween.
The telephone switch 40 of Figure 3 becomes an ITG 54. More specifically, the incoming calls are routed through the telephone switches 42 to the interface II for conversion in to a telephone trunk signal Tl for application to the PSTN 44 in the same way illustrated in Figure 3. Likewise, the microprocessor 46 controls the trunking in the interface II and sends control signals through the interface 13 in the SS7 protocol for application to the IN 48.
However, the addition of an interface 12 integral with the ITG 54 and under the control of the microprocessor 46 converts the circuit switched telephone signals directly to the IP for
application to the Internet. This direct conversion of the outgoing calls to the IP before converted to a trunk format within the telephony switch converts the telephony switch to an ITG and obviates the need to convert the trunk signal Tl output from the interface II to IP.
The implementation of the ITG 54 shown in Figure 4 may be as shown in Figure 5 where a conventional telephone switch 60 such as the Harris Corporation 20/20 may be provided with an Integrated Network Server ("INServer") 62 as a card which can be inserted into the back plane of the switch 60.
The INServer 62 has access to all of the voice paths within the switch 60, thereby eliminating the need for trunk interfaces for interactive control of the IP packets.
An ITG card 64 such as the IP Telephony Card available from Analogic Corporation may be inserted into the INServer 62, thereby effecting the direct conversion of the PCM signal from the telephone switch to the internet packets necessary for acceptance by the Internet. By the use of this card, the switch itself may provide a IP trunk directly, making the telephony switch an ITG.
This integration of the ITG into the telephony switch reduces the number of expensive parts and the cost of administration of the system. In addition, it increases the robustness of the system by making the redundant power supplies of the switch available to the ITG, protects the ITG by inclusion in the large and strong physical case of the telephone switch, protects the ITG from electromagnetic radiation, limits the potential of electromagnetic radiation from the ITG, etc.
The higher level of flow control provided by the integrated conversion permits multiple IP connections, alternate routes and least cost routing.
A further advantage is realized in obtaining type approval of the equipment in that existing telephone equipment has generally been approved for service throughout the world and a modification to such a switch is easier than obtaining approval of additional equipment.
While preferred embodiments of the present invention have been described, it is to be understood that the embodiments described are illustrative only and the scope of the invention is to be defined solely by the appended claims when accorded a full range of equivalence, many variations and modifications naturally occurring to those of skill in the art from a perusal hereof .