COURIER HIGH SPEED MODEMS
APPENDIX H. MODEM TESTING
Testing is available with the &T command or Register S16. All loopback testing conforms to
Only one test can be performed at a given time. If you send a test command while the modem is in test mode, you'll receive an ERROR message.
NOTE: Testing is not available when the modem is in
synchronous mode: &M1, &M6, &M7.
TESTING WITH &T
The tests supported through the &T command include analog loopback, digital loopback and remote digital loopback. Users can key in their own data during testing, or use the modem's internal test pattern and error detector.
In all cases, disable error control before testing. If the modem is detecting errors and retransmitting the affected data, your results will be invalid.
During testing, the MR status light flashes.
Ending a Test⎯&T0, S18
Issuing the &T0 command terminates a test. Alternatively, set Register S18 to a specified number of seconds, for example, S18=10. When the 10 seconds are up, the modem automatically ends the test and returns to Command mode. If the test was Analog Loopback, the &T0 command hangs up the modem. If the test was Digital or Remote Digital Loopback, issue an ATH command to hang up the modem, or an ATZ command to hang up the modem and reset it to its defaults.
NOTE: If you use the S18 test timer, but in the process of testing you issue an ATZ command, S18 resets to zero and the timer is disabled. You cannot store a value for S18 in nonvolatile memory; its
Modem Testing
