Loopback Tests - PictureTel Concorde 4500 Servicing Manual

Concorde•4500
with V.35

Loopback Tests

3. Try flipping the cables at the terminal adapter, since the problem
seems to be at this connection. The cable that was originally
connected to Port 1 on the Concorde•4500 and Port 1 on the
terminal adapter is now connected to Port 2 (on both ends.) Do the
same for the other cable. Connect it to Port 1 on the
Concorde•4500 and Port 1 on the terminal adapter.
Port 1
Port 1
Port 2
Port 2
Terminal Adapter
The result is that Port 1 will not sync up. The problem has
followed the same port (Port 1) on the terminal adapter. By
experimenting with the cables you can determine that there will
be a problem with any cable connected to Port 1 on the terminal
adapter.
Loopback tests verify the operation of various components in the
data path of the system. Failure of a loopback test indicates that one
of the devices in the data path failed to transmit the data.
Typical reasons for device failure are:
The device is not plugged in or turned on.
One or more cables are loose or disconnected.
The device is not set properly (it may have been left in a test
mode).
The device is faulty.
Loopback Tests
NT1 Network
4-31