Allied Telesis AT-2746FX - Manual (Page 190)

Chapter 11: Troubleshooting
190
ˆ For a fiber optic port, verify that the operating specifications (for
instance, wavelength and maximum operating distance) of the fiber
optic port on the remote device are compatible with the fiber optic port
on the network adapter card. For example, a fiber optic port with an
operating wavelength of 1310 nm will not function if connected to a
remote fiber optic port with an operating wavelength of 820 nm. Refer
to Chapter 1, “Network Adapter Card Overview” on page 13 for
operating specifications of the fiber optic ports.
ˆ For a fiber optic port, use a fiber optic tester to test signal attenuation
on the cable. If signal strength is too low, you have either exceeded the
permitted maximum length of the fiber optic port or the fiber optic cable
has a problem, such as too many splices. Refer to Chapter 1,
“Network Adapter Card Overview” on page 13 for operating
specifications of the fiber optic ports.
ˆ For a fiber optic port, check to be sure that the two strands of the fiber
optic cable are connected correctly on both the network adapter card
and the remote device. Duplex SC and ST ports consist of two
separate connectors, as shown in Figure 114. Each connects to a
different fiber strand. One is for receiving data and the other is for
transmitting data. When connecting a fiber optic cable to a duplex ST
or SC port, the strands have to cross. That is, the strand connected to
the transmitter connector on the port on the network adapter card must
connect to the receiver port on the remote device, while the strand
connected to the receiver connector on the port on the network
adapter card must connect to the transmitter port on the remote
device.
Figure 114. Duplex ST and SC Ports
1 TX RX
1 TX RX
Duplex ST Port
Duplex SC Port