User's Manual

4.2 Local Analog Loopback with Self-Test
The local analog loopback with self-test checks the integrity of the local modem. In this test, an internally
generated data pattern of alternate binary ones and zeros (reversals) at the selected bit rate is looped through
the internal analog loop inside the local modem to an internal error counter as shown in Figure 4-2. An error
count of 255 indicates that 255 or more errors were detected.
Example-the test timer is disabled and 12 errors are found during the test
Command: AT&Q0<CR>
ATS18=0&T8<CR>
Result: OK
Command: AT&T0<CR> (ends the test)
Test result: 000
Result code: OK
5 - THROUBLESHOOTING GUIDE
This chapter describes common problems in the installation, configuration and regular usage of your
Fax/Data Modem. To test the Fax/Data Modem, a communication software package is needed and the
package must include a mode that allows you to operate your Fax/Data Modem by directly issuing internal
commands to the modem.
Follow the procedures in the following sections to resolve these common problems:
No Response From Your Modem
1. If you are using the internal add-on card modems, make sure that the COM port address you have
set your modem to corresponds to the appropriate selection in the communications software which
you are using.
2. Issue the ATZ command to reset your modem. The returned result code should be "0" or "OK"
depending on what communications program you are using. Your modem is OK if you get one of
these responses. If there is no response after issuing the ATZ<CR>, continue to the next step.