Ericsson ZAT 19.2 Operation Manual page 280

(fatests
14.8 Remote digital loopback
The purpose of this test is to check your own data terminal (DTE),
your own modem (DCE),the remote modem and the telephone line.
This test is initiated by your own DTE sending a test message to the
remote modem. The remote modem loops this message back to the
local modem, and the DTE will compare the transmitted data with
the received.
Remote
Modem Modem
"| —_____» |Modulator ___, | Modulator ¢_
Demodulator re Demodulator,
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 command)
Test timer disabled - example 1
= Enter:
eee5
5
| The modem returns to command state.
|
The modem answers OK Ready to continue.
2Enter:
s 8=08T6 pa] $18=0 disconnects test timer.
&T6 selects remote digital loopback.
Test indicator lights
= Write for example:
This is atest [The same text will appear on the screen
=>Enter:
pe Escape sequence
Ses Eogh o r c s The modem returns to command state
The modem answers OK
14-1 0 LZTR104006 R1.00
Zat 14.4/14.4-7 and 19.2/19.2-7