Local Analog Loopback Test (V.54 Loop 3) - Multitech MULTIMODEM MT5634ZBA-USB User Manual

MT5634ZBA-USB User Guide

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 modem's receiver, converted into digital
form, and then sent to your monitor for verification. No connection to the phone line is
required.
Test Procedure
1. Connect the modem to your computer. Using your communication program, set the
2. Type AT&T1 and press ENTER. This places your modem in analog loopback mode
3. Note that the CD LED is on. If you are set for 14,400 bps or higher, a speed LED
4. Enter characters from your keyboard. For this test, typing multiple uppercase U
5. To exit the test, type the escape sequence +++AT and press ENTER. This puts the
6. Your modem passes this test if the data received on your monitor are the same as
54
AT&T1
CONNECT
UUUUUUUUU
UUU
Computer or Terminal
Figure C-1. Local analog loopback test.
desired baud rate and go into terminal mode.
in the originate mode. A CONNECT message should appear on your display. The
modem is now out of command mode and in a pseudo-online mode.
should be on. If the CD LED is not on, there is a defect in your modem.
characters is a good way to send an alternating test pattern of binary ones and
zeros. The characters entered should be displayed on your monitor. The TD and RD
LEDs should flash when a character is entered.
modem in online command mode. Then type either AT&T or ATH to return to
command mode.
the data entered from your keyboard. If different data appear on your monitor, your
modem is probably causing the problem, though it could also be your computer. If
your modem passes this test, but you are receiving errors while on line, the remote
modem or the phone line could be at fault.
Digital Analog
Local MultiModem