HP Series 200 Installation Manual page 62

FDDI Port
"Thru"
Figure 2-6. FDDI "Thru" and "Wrap A" Operation
Thru (green): When lit, this LED indicates that packets are being
received on the primary input line of port A and transmitted on the
primary output line of port B.
Wrap A and B (green) LEDs:
has occurred in the FDDI ring or the attached neighbor's hardware has
failed. In these cases the router is transmitting and receiving on the
indicated port only (and not on both ports). In this case, the indicated
port is receiving on the input line and transmitting on the output line for
that port. This occurs in either of the following cases:
The unlit port is not communicating.
A Dual Attach Station (DAS) attached to the unlit port is not
functional.
These cases occur, for example, when the cable connection to the unlit
port is interrupted or when a DAS connected to the unlit port is down.
Sig Det (green): Signal Detection is lit when the router detects an
incoming signal on the FDDI port, and should be lit continuously.
Ring OP (green): The Ring OP LED is continuously lit if the router
is inserted and operating in an FDDI ring and is in either Thru or Wrap
mode.
Interpreting Back-Panel LEDs
If either A or B is lit, either a break
Router Operation
"Wrap"
2-11