US Robotics COURIER - Page 180

&T7
I~
...
COURIER HIGH SPEED MODEMS
testing with your modem, the problem may also lie with
your modem.
5. Reset DIP switch 9 OFF unless you normally set that switch
ON, and issue ATZ to the modem to initiate the new setting.
Reset the modem to &M4 unless you used the reset
command, ATZ.
This test option causes the modem to send an internal test
pattern through the Remote Digital Loopback. An internal error
detector counts any errors and, when the test is ended, sends the
number of errors or 000 (no errors) to the screen.
You don't need to type anything during this test. The modem
sends only its final error count to your screen .
1. Set the software to 2400 bps or lower. Set the modem to
&MO. If you wish, set the S18 timer.
Establish a connection with the remote modem. If you
haven't already done so, arrange with the remote user to
cooperate with your testing and, if necessary, set the remote
modem to acknowledge the RDL request. For example,
older USRobotics high speed modems need to be set to
S16=8.
2. Bring the modem back to Command mode with the +++
escape code. Then send it the AT & T7 command. The
modem enters RDL mode and the MR status light flashes.
The modem sends its internal test pattern to the remote
.,_ modem, which loops it back to your modem. You will not
see the data on your screen.
3. End the test. If you set S18, the modem automatically stops
the test when the timer times out. If you didn't set Register
S18, type AT&TO 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. If you issue an invalid command, the
modem sends an ERROR message.
When you terminate the test, the modem returns a three-
digit code, followed by OK. A code of 000 indicates no
errors were found. A code of 255 indicates 255 or more
errors.
Modem Testing F-7