There could be several reasons for not seeing the expected signal. Check the following.
1. Verify the fiber cabling between the STC Live Probe and the Switch or Router. One common problem is the fiber cabling is not terminated to the correct port on the switch.
2. Connect to the TL1 port of the STC Live Probe. Login to the unit and issue 'REPT-DIAG:::CTAG'.
STAC-6500-1 11-07-05 20:17:20
M CTAG COMPLD
SELF TEST OUTPUT:
NETWORK INTERFACE CARD
PORT-1: BOTH, 1000/FULL, GTP
PORT-2: BOTH, 1000/FULL, NO SFP
CLOCK - NOT SYNCHRONIZED
In the above example, the lines of interest are the PORT-x lines, specifically the last field.
PORT-1 is connected properly to the Switch at 1000 Mbps and Full Duplex. The 'GTP' indicates the port is locked to the comma sequence. This is the desired status for a properly-functioning link.
The "NO SFP" shown for PORT-2 indicates SFP is not detected. Normally this means there is no transceiver installed in the Port.
A status of LOS in the last field indicates transceiver is installed but either no cable is connected, optical power is too low, or it is an incorrect link type.
A status of LOF in the last field indicates the port is locked to the comma sequence but an error was encountered. It can be caused by protocol violation or bit errors on the link, possibly indicating an optical power problem
3. In STC Live T&D, check how the Test Link is built. Verify the port on the Switch and the port on the STC Live Probe is correct.
4. The problem could be occurring because of the configuration of the interface/port on the Switch. Verify things such as VLAN Tagging, Duplex, Port Speed,ect.