DE19545239A1 - Universal testing device for telecommunications appts. - Google Patents

Abstract

The testing device provides all the normal testing and measuring functions provided by a hand-held testing device, a digital multimeter, an analogue measuring device, a level meter, a tone generator and a frequency indicator. The control of all the different functions of the device is effected via a microcontroller.Pref. a number of different modules for providing respective functions are coupled to the microcomputer via a module interface, allowing unlimited expansion of the function of the testing device.

Description

In the technical field service for interference suppression and installation of telecommunication lines, terminals and PBX systems, numerous measuring and testing work is required. So far this has required that Carrying several devices such as test handset, moving coil measuring instrument, digital multimeter, Tone generator, various test cords, etc. In addition, technical development (e.g. ISDN technology, digital PABX systems, etc.) constantly looking for new devices and processes in the Service area.

With the invention specified in claim 1, the aim was pursued, all of the above. Functions summarized in one unit, with special emphasis on easy handling and Operation as well as robustness was laid.

The advantage of such a solution is that the service technician when carrying a Device all the above Functions are available. In addition, by simple and clear operation Mistakes and diagnoses avoided as well as the expenditure of time reduced for various measuring and testing work.

Should the above Device manufactured and sold in series, so it represents a user affordable alternative to procuring a wide range of devices.

The following functions were implemented:

⚫ Test handset

• - Hearing-speaking operation via loudspeaker
• - Dialing mode with keypad
• - OB operation, supply of a passive remote station possible
• - Possibility of DC-free, capacitive switching on in one line

⚫ measuring device

• - Voltage, current, resistance, and frequency measurement
• - Automatic detection of DC and AC voltage / current
• - automatic measuring range switching
• - Voltage values can also be called up as an absolute level in dBm and Np
• - Easy to read 7-segment LED display
• - Measured values are also displayed analogously as a moving illuminated dot

⚫ tone generator

• 1 kHz generator

⚫ module interface

• - Practically unlimited functional expansion possible due to free configurability

⚫ power supply

• - optionally via 6V power supply or 5 R6 cells or batteries

The further embodiment of the invention described in claim 2 enables in With regard to upcoming and already existing technical innovations in telecommunication cations a practically unlimited extension of the functional possibilities of this device. This allows the above-mentioned Advantages by adding additional modules also a very inexpensive alternative to the procurement of new measuring and testing systems be created.

Since each additional module contains its own control software and measurement hardware, it is free Configuration possible.  

An embodiment of this invention is described in more detail below.

Fig. 1 shows a view of the controls of the sample device.

An 8-bit microcontroller type 80c535 was used to control all functions used. This has the advantage over other systems that many are needed for implementation the required peripheral components such as B. A / D converter, Timers, input and output ports etc. are already integrated in the controller chip.

As a result, the hardware expenditure could be reduced to a minimum.

The measuring circuits for current / voltage and resistance were designed so that they could easily be connected to the controller board.

Fig. 2 shows the circuit diagram for the current / voltage measuring circuit. All switching contacts are controlled via relays, which are connected to the digital outputs of the controller. A non-inverting amplifier (OPV 3 ) with a variable gain factor converts the input signal into a range of 0-5 V.

This is an OPV B061 with input offset compensation.

A precision rectifier is used for averaging during AC voltage / current measurement and as reverse polarity protection and polarity indicator for DC voltage / current measurement. In contrast to the usual measuring circuits, the rectifier was arranged behind the measuring amplifier. As a result, disturbances in the rectifier OPV such as offset voltages and noise are not amplified and can be neglected. A double OPV B062 without offset compensation is used for the rectifier (OPV 1/2 ). OPV 1 provides the output measurement signal for the controller. An RC combination is connected downstream for smoothing pulsating signals (rectified AC voltage). At the output of OPV 2 there is either ground potential with a positive input variable or negative voltage with a negative input variable. A subsequent phase rotation circuit (transistor T1) converts the negative output voltages of the OPV into positive voltages. These are fed to the analog input 1 of the controller for polarity detection and AC identification. If there is a change within a certain time interval, the controller identifies the measurement signal as alternating current / alternating voltage and opens the relay = / ∼. As a result, the DC components are filtered out and the voltage divider Ru2 becomes effective. In connection with an internal reference voltage reduction, the form factor is taken into account.

This design of the measuring circuit enables automatic measuring range switching and Equal / change size detection.

Fig. 3 shows the circuit diagram of the resistance measuring circuit.

It is a circuit commonly used in digital multimeters. The measuring range is switched over by changing R _E according to the formula:

The counting frequency measurement was chosen to implement the frequency measurement function ( FIG. 4). In addition to the input circuitry, all components could be implemented in software using the controller.

The module interface ( Fig. 5) realizes the functions described in claim 2. In order to enable free configuration and connection of the additional modules to the microcontroller, all digital and analog inputs, which are not yet used, control lines as well as data and address lines are brought to the interface. The module can also use the internal measuring circuit.

When switching to "external", the internal EPROM is switched off and the microcontroller takes effect towards the eprom of the additional module. The input signal is from the internal measuring circuit Cut.

The additional module contains:

• ⚫ The measuring circuit with the desired function
• ⚫ An eprom with the corresponding control program
• ⚫ The interface for plugging onto the interface

In FIG. 6, the principal applications are integrated headsets device shown.

The internal control software of the microcontroller is very easy to use extensive automation. The individual functions can be activated by pressing a button such as current and voltage measurement, resistance measurement and frequency measurement activated will. Voltage values can also be represented as absolute levels in dBm and Np will.

Claims (3)

1. Universal testing device for telecommunications equipment, characterized in that all essential functions of known testing and measuring equipment in telecommunications technology such as:

• - test handset
• - digital multimeter
• - Analog measuring device
• - level meter
• - tone generator
• - frequency meter

were combined in one device, with great emphasis on robustness, comfortable Operation and compact, handy design was laid. A microcontroller controls all functions of the device. 2. Universal testing device according to claim 1 characterized, that m.H. a module interface in connection with the microcontroller of the above A practically unlimited function expansion is possible.