Patent ID: 6282239
Filing Date: 2001-08-28
Classification: H04L

Abstract:
A data processing system comprising:a processor;a storage device;a modem, wherein the modem is configured for connection to a telephone network;an input/output adapter;a bus, wherein the processor, storage device, modem, and input/output adapter are connected to the bus;a remote control, wherein the remote control provides interaction and control of the data processing system and sends and receives signals to and from the input/out adapter;instruction means for accessing a remote data processing system, wherein the instructions are stored on the storage device; andtesting means for testing whether an electrical connection to a telephone network is present, wherein the testing means includes:an operational amplifier having a first input connected to a first modem input conductor of the modem input;a first resistor connected between an upper power supply voltage and a second input of the operational amplifier;a second resistor connected between a lower power supply voltage and the second input of the operational amplifier, wherein the first and second resistors are sized to create a voltage drop across the second resistor equal to the threshold voltage and a second modem input conductor of the modem input is connected to an end of the second resistor connected to the lower power supply voltage; anda Schmidt trigger connected to an output of the operational amplifier, wherein the output of the Schmidt trigger produces a result of the comparison of the voltage on the modem input to the threshold voltage.