COURIER HIGH SPEED MODEMS
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&T0 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.
If you've performed an Analog Loopback and know your modem is working properly, errors indicate a problem with either the phone connection or the remote modem.
4.Reset DIP switch 9 OFF unless you normally operate with it ON. Issue an ATZ command to initiate the new switch setting. Reset the modem to &M4 unless you've sent it the ATZ reset command.
TESTING WITH REGISTER S16
Register S16 is a
Bit Value Function
01 Analog Loopback (AL)
12 Dial Test
24 Test Pattern
38 Remote Digital Loopback (RDL)
