Total Control MP/16, Operator'S Manual

Page: 154 / 182

E-4 Modem Testing
4
If there were no errors, reset the modem to &M4 for error
control unless you issued the ATZ command.
Digital Loopback
 
&T3
If your modem has passed the AL test, this test can help you locate
a problem with a remote modem or the tele phone channel. Figure
E-2 shows the data flow during DL testing.
Figure E-2. Data Flow During Digital Loopback
NOTE:
This test requires the modem to establish a connection
and return to online-command mode in response to the +++
escape code. DIP switch 9 must be set ON so that the modem
does not hang up on receipt of the escape code. After you change
the switch, issue ATZ to the modem to initiate the new setting.
1 Set the modem to &M0, to disable error control. Establish a
connection with the remote modem.
2 Bring the modem back to Command mode with the +++ escape
code. Then send it the AT&T3 com mand. The modem enters
DL mode and the Modem LED glows green.
3
The remote user should type a short message. It will be looped
back by your modem's trans mitter for verification on the
remote screen. You will not see the message or any other data.
4 When the remote user has completed the test, issue the A T&T0
command to end the test, or send either ATH or the command
that resets the modem, ATZ. The latter two commands end the
test and hang up the modem. The modem responds OK.
5 Reset DIP switch 9 OFF if you normally use the factory default.
Reset the modem to &M4 unless you used the reset command,
ATZ.