10
Pseudorandom Bit Sequence (PRBS) Testing
To test using the internal Pseudorandom Bit Sequence source, ensure that the Central
Office and the Customer Premises equipment are configured for loopback. The
iMcV-DS3/E3/STS-LineTerm modules should be set to normal default mode. On the
HOST iMcV-DS3/E3/STS-LineTerm module, set the Transmit Coax Data Source to
“Transmit Pseudorandom Sequence" (S1-6, S1-7=OFF). Verify the PRBS LED comes
ON at the HOST iMcV-DS3/E3/STS-LineTerm module to validate the coax wire
connections to the Central Office. Verify the PRBS LED comes ON at the REMOTE
iMcV-DS3 module to validate the coax wire connections at the Customer Premises
equipment and the fiber line going to the REMOTE iMcV-DS3/E3/STS-LineTerm
module. The fiber line returning from the remote iMcV-DS3/E3/STS-LineTerm
module is validated by verifying the RM LED is ON at the HOST iMcV-DS3/E3/STS-
LineTerm module. At this point all connections for the channel have been verified
.
11
Troubleshooting
General Troubleshooting
•
The Coax Port can easily be tested using the internal PRBS signal generator and
detector and a physical wire loop on the coax interface.
•
The Fiber Port is internally tested at all times by a working pair of units. With one
unit configured for Local Management (Switch 10 set OFF) and the other for
Remote Management (Switch 10 set ON), the fiber line is verified if the “RM” LED
is ON at both ends of the fiber line. Under normal operation only the “RM” LED
is ON at both HOST and REMOTE.
•
To test a media converter by itself, first make sure you have an appropriate fiber
patch cable, then follow these steps to test:
1.
Connect the media converter to the BNC device with a coax cable.
2.
Loop a single strand of fiber from the transmit port to the receive port of your
media converter.
3.
Verify that you have a valid connection for both the BNC and fiber ports on
your media converter. (No “ER” or “LOS” LED ON)
•
If there is trouble with link connectivity, verify your cable connection and DIP
Switch setting are correct.
•
Use the following LED indications to identify the fault location:
*DIP Switch 4 must be set to ON for Fault Loopback to operate as illustrated above.
