18 Network Service Module
C613-03022-00 REV K
PIC LEDs

The following LEDs report operations and faults on PICs, and may be helpful

when diagnosing possible AT-AR040 NSM operational faults. The LEDs are

located on the faceplate of the respective PIC. The AT-AR024 ASYN4 PIC does

not have LEDs.

Table 6: AT-AR020 PRI E1/T1 PIC LEDs
LED Function
D Data [ISDN mode only] Lit when HDLC packets are being exchanged between the
switch or router and the ISDN switch over the D (signalling) channel.
B Data Lit when HDLC packets are being exchanged between the switch or router
and another end system device (normally another switch or router) over any
of the B (data) channels.
Active Lit whenever operational (i.e., no RAI or AIS set) frames are being received
on the respective interface (PRI 0 or PRI 1) from another source.
NT [ISDN mode only] Lit when the PRI1 is operating in NT mode. This LED
should not be lit during normal operation.
Table 7: AT-AR021(S) BRI-S/T PIC LEDs
LED Function
B1, B2 For on-demand ISDN, lit when there is a call up over the respective B
channel and flashing when data is being exchanged.
For permanent circuits, lit when HDLC packets are being exchanged
between the switch or router and another TE end system device (normally
another switch or router) over the respective B (data) channel.
Active Lit when the BRI has successful ly completed the exchange of INFO 1 and
INFO 2 signals, and INFO 3 and INFO 4 signals are present on the link. This
means that the ISDN interface is correctly connected to a working NT
device.
D Lit when HDLC packets are being exchanged between the switch or router
and the ISDN switch over the D (signalling) channel.
Table 8: AT-AR021(U) BRI-U PIC LEDs
LED Function
B1, B2 Lit when HDLC packets are being exchanged between the switch or router
and another TE end system device (normally another switch or router) over
the respective B (data) channel.
For ISDN, lit when there is a call up over the respective B channel and
flashing when data is being exchanged.
Active Lit when the U interface is in the Activated state (i.e., it is in a fully
operational at layer 1).
D Lit when HDLC packets are being exchanged between the switch or router
and the ISDN switch over the D (signalling) channel.