Chapter 4 - Testing Your Modem; Local Analog Loopback Test/V.54 Loop 3 - Multitech MULTIMODEM MT5600ZDX Owner's Manual

MT5600ZDX Owner's Manual

Chapter 4 - Testing Your Modem

Local Analog Loopback Test/V.54 Loop 3

In this test, data from your computer or terminal is sent to your
modem's transmitter, converted into analog form, looped back to the
receiver, converted into digital form and then received back at your
monitor for verification. No connection to the phone line is required.
See Figure 4-1.
Figure 4-1. Local Analog Loopback Test
The test procedure is as follows:
1. Connect the modem to your computer. With your communication
software, set the desired baud rate.
2. Type AT&T1 and hit ENTER. This places your modem in Analog
Loopback mode, in the Originate mode. The modem is now out of
the Command mode and in a pseudo On-Line mode.
3. Once you receive a connect message (if responses are enabled),
enter data from your keyboard. For this test, typing multiple upper
case "U" characters is a good way to send an alternating test
pattern of ones and zeros.
4. For a more complete test, you should also test the modem in
Answer mode. To do this, you must "escape" from Originate mode
by entering an Escape Sequence ( +++ ) . Then type AT&T1 and
hit ENTER to place the modem in Analog Loopback mode, in the
Answer mode. Then repeat step 3.
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