Dataplex DPX-213, User Manual

Page: 64 / 93

TESTING and DIAGNOSTICS
Section 7
7-2
Copyright (C) Dataplex Pty Ltd
7.2 Local Analog Loopback (ALB)
Local Analog Loopback will test the analog and digital performance of the DPX-213
modem up to the line interface hybrid. Analog Loopback is controlled with the AT&T1
command.
If the DPX-213 is configured for switched network operation, the modem must be off-line
for this test to work properly. If you are on-line the modem will not go into loop but will
issue "CONNECT 2400" and revert to the On-line Data Mode (equivalent to typing ATO).
To enter the Analog Loopback, type the command string
at&t1K
.
In synchronous or asynchronous operation, the modem will respond with an asynchronous
"LOOP GRANTED" message. All characters from your keyboard will be echoed back to
you. To disable the messages in synchronous Mode, use the ATQ1 command. Exit the test
by typing the 'pause'
+++
'pause' escape sequence then AT&T0.
Figure 7.1 Local Analog Loopback
7.3 Remote Loopback Response
When power is applied, Remote Loopback is disabled. Therefore, your modem cannot be
put into loop from the remote end nor can the command AT&T6 be issued locally.
To enable Remote Loopback, type the command string
at&t4K
.
AT&T5 or AT&F disables Remote Loopback.