Ericsson ZAT 19.2 Operation Manual page 283

14.9 Remote digital loopback with test pattern
The purpose of this test is to check the remote modem and the
tetephone line. This is initiated by your own modem sending a
standard test message to the remote modem.
The remote modem loops this test message back to the local
modem, which compares transmitted data with received data and
counts the number of faults
Remote
Modem Modem
Preconditions:
Your own modem must have established a connection with the
remote modem ( A-mode or B-mode ).
Echo must be enabled ( E1 command) . The remote modem
must be set to accept request for a Remote Digital Loopback
(&T4 commang ) .
Test timer disconnected - example 1:
=Enter:
o e | The modem returns to command state.
$18=0 disables the test timer.
&T7 selects remote digital loopback
= ] with test pattern.
| Test indicator lights
AT&TO reall ce ae &TO terminates the test.
The modem answers 7 000 No faults detected
OK Test terminated
Alternative 2
The modem answers 007 7 faults detected
OK Test terminated