2.3.4.4 Adapter Cable and Modem Cable Testing
The adapter cable and modem cable loopback test use the same remote console
command (TEST) on different loopback points. Run the adapter cable loopback
test first. To run the test, perform the following steps:
1.
Detach the adapter cable from the modem (or modem cable).
2.
Put the appropriate loopback connector on the end of the adapter cable. ~
contains a list of loopback connectors.
3.
Enter the following command at the console:
TEST DATA_LOOPBACK/CH
n
Replace n with the number of the synchronous line (0, 1, 2, or 3).
If this test fails, go to Section 2.3.5. If this test succeeds, run the modem cable
test (if there is a modem cable) by performing the following steps:
1.
Reattach the modem cable to the adapter cable.
2.
Detach the modem cable from the modem.
3.
Put the appropriate loopback connector on the end of the modem cable.
4.
Enter the following command at the console:
TEST DATA_LOOPBACK/CH
n
As before, replace n by the number of the synchronous port.
If this fails, go to Section 2.3.5. If this test succeeds, reconnect the cable to the
modem, and test the local modem.
2.3.4.5 Local Modem Testing
A modem control signal sent to the modem from the DEC MicroServer can
put the modem into a loopback mode. However, not all modems recognize
this signal, and some need to be set to loopback manually. The modem
manufacturer’s literature should tell you what loopback facilities are available.
The TEST command you use depends on whether the modem recognizes the
loopback signal from the DEC MicroServer.
•
If your modem recognizes the loopback signal, read Section 2.3.4.5.1.
•
If your modem does not recognize the signal, read Section 2.3.4.5.2.
•
If your modem has no test facilities at all, read Section 2.3.4.5.3.
2–14 Using Loopback Tests
