Total Control MP/16, Operator'S Manual

Page: 155 / 182

Modem Testing E-5
&T4, &T5
The &T4 option causes the modem to grant a remote modem's
request for a Remote Digital Loop back test.
The &T5 option cancels &T4, and the modem fails to recognize
such a request. This is the default so that your modem isn't subject
to another user calling and tying up your modem without your
permission.
Remote Digital Loopback
 
&T6, &T7
This test, like the local digital loopback test, verifies the condition
of both modems and the phone link. Data flow is shown in Figure
E-3.
Figure E-3. Data Flow During Remote Digital Loopback
The request for and granting of Remote Digi tal Loopback testing
requires that both modems use ITU-T V.22 stan
dard signaling.
The
test must be performed at 2400 bps or lower.
If the remote modem
does not have the capability or is not set to respond (&T4), you will
get an ERROR result code.
As with Analog Loopback, there are two Remote Digi tal Loopback
options. If you select &T6, you send keyboard data to the modem
and verify it when it is returned over the phone lines and to your
screen. If you select &T7, the modem sends its internal test pattern
and returns an error count to your screen.
NOTE:
Both test options require 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. If
necessary, set the switch ON and then issue the ATZ command to
the modem to initiate the new switch setting.