Patent ID: 6285744
Filing Date: 2001-09-04
Classification: H04M

Abstract:
A telephony test system for testing a telephone circuit having a tip and a ring, the telephony test system comprising:a programmable gate array (PGA) having a plurality of logic gates and a plurality of input/output pins, with the logic gates programmably configurable in an array configuration, with the array configuration programmably connectable to the plurality of input/output pins of the PGA;a controller connected to the PGA via a bus;a digital-to-analog converter (DAC) having an input connected to an output of the PGA;an analog-to-digital converter (ADC) having an output connected to an input of the PGA; anda first driver circuit having a first input connectable to an output of the DAC, a first output connectable to an input of the ADC, a second output connected to one of the tip and the ring and a second input connectable to the one of the tip and the ring, with the first driver circuit having a control input adapted to receive an impedance adjust signal, wherein:the controller causes the PGA to configure the plurality of logic gates in a desired array configuration, and causes the PGA to connect the desired array configuration and the plurality of input/output pins in a desired manner;as a function of the controller programming thereof, the PGA controls the DAC to generate an output voltage to the first driver circuit and controls the ADC to sample from the PGA a signal corresponding to a signal impressed on the one of the tip and the ring;the first driver circuit generates to the one of the tip and the ring a voltage corresponding to the output voltage generated by the DAC and the impedance adjust signal received at the control input; andthe first driver circuit generates to the one of the tip and the ring an output impedance corresponding to the impedance adjust signal received at the control input.