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MultiModemZPX User Guide | C Loopback Tests |
Appendix C: Loopback Tests
Introduction
Each time you turn on your modem, it performs an automatic
In a loopback test, data from your computer loops through the circuits of your mo- dem and/or a remote modem before it appears on your monitor. When the loop has been completed, the data on your PC’s monitor should match the original data.
The local analog loopback test allows you to verify that the modem’s transmitter and receiver circuits are functioning properly.
The remote digital loopback test allows you to verify that the local computer or ter- minal, the serial ports, the local and remote modems, and the transmission line be- tween them are functioning properly.
The local digital loopback test allows you to verify that the remote computer or ter- minal, the serial ports, the local and remote modems, and the transmission line be- tween them are functioning properly.
Local Analog Loopback Test (V.54 Loop 3)
In this test, data from your computer or terminal is sent to your modem’s transmit- ter, converted into analog form, looped back to the modem’s receiver, converted into digital form, and then sent to your monitor for verification. No connection to the phone line is required.
AT&T1
CONNECT 9600
UUUUUUUUUUUU
Digital Analog
Computer or Terminal | Local MultiModem |
Figure C-1. Local analog loopback test.
Test procedure
1.Using a communications program, set the baud rate to 9600 and go into terminal mode.
2.Type AT&T1 and press ENTER. This places your modem in analog loopback mode in the originate mode. A CONNECT message should appear on your dis- play. The modem is now out of command mode and in a
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