COURIER HIGH SPEED MODEMS
Modem Testing H-11
Initiating Modem
1. If DIP switch 9 is OFF, set it ON so that it does not hang up
on receipt of the +++ escape code. Issue an ATZ command
to initiate the new switch setting.
2. Set the software to 2400 or 1200 bps. The ITU-T-specified
RDL signals are defined only for connections at 2400 or 1200
bps.
3. Disable error control by setting the modem to &M0. Then
establish a connection with the remote modem.
4. Bring the modem back to Command mode by sending it the
escape code: one second of no data, three pluses (+++), and
another second of no data.
5. When the OK result code appears, send the modem the
following command:
ATS16=8 O
The modem enters RDL mode (S16=8), the MR status light
flashes, and the modem goes back online (O command).
Then it transmits the ITU-T-defined RDL signals, causing
the remote modem to enter RDL mode.
6. Type any data at the keyboard. (Or send the test pattern.)
7. To end the test, send the modem the +++ escape code again
to bring it back to Command mode.
8. When the modem sends the OK result, reset the modem to
Data mode with the following command:
ATS16=0
The modem signals the responding modem that RDL
testing is over. Terminate the call as you normally would,
and reset the modem to its normal error control setting,
&M4 or &M5.
Or, if you wish to resume data transmission with the remote
modem, add the O command to the ATS16=0 string to
return the modem online.