Installation guide

4-38 Cisco IGX 8400 Series Reference
Network Trunk Module
For details on the significance of LEDs, see the Cisco IGX 8400 Series Installation manual.
The alarms and line conditions that the NTM monitors include those in the list that follows. To view
errors on a trunk, use the dsptrkerrs command. To see a list of the (user-specified) errors that
dsptrkerrs can display, use dsptrkstatcnf.
• E1 CRC4 errors
• T1 bipolar violations
• Near end and far end frame alarms
• Alarm information signal (AIS)
• Loss of signal (LOS)
• Line signal frame sync losses
• Packet out of frame
T1 Interface Card (BC-T1)
The T1 trunk interface card (BC-T1) card terminates a single 1.544 Mbps T1 trunk line on the NTM.
The BC-T1 can reside in any rear slot 3 through 8 in an Cisco IGX 8410, 3 through 16 of the Cisco
IGX 8420, or 3 through 32 of the Cisco IGX 8430. The BC-T1 connects directly to the NTM.
The BC-T1 provides the following:
• Trunk line interfaces to T1 trunks at 1.544 Mbps
• Software selectable AMI or B8ZS (bipolar 8 zero-suppress) line code
• Software selectable D4 or ESF (extended super-frame) framing format
• Configuration as either full or fractional T1 service
• Extraction of receive-timing from the input signal for use as the node timing
• Software selectable line buildout for cable lengths up to 655 feet
• Passes line event information to the front card
B8ZS supports clear channel operation because B8ZS eliminates the possibility of a long string of
0s. B8ZS is preferable whenever available, especially on trunks.
The BC-T1 supports two clock modes. The clock modes are normal clocking and loop timing.You
select the mode through software control. With normal clocking, the node uses the receive clock
from the network for the incoming data and supplies the transmit clock for outgoing data. The node
can use the receive clock to synchronize itself with the network.
With loop timing, the node uses the receive clock from the network for the incoming data and
redirects this receive clock to time the transmit data.
BC-T1 Faceplate Description
Figure 4-23 and Table 4-17 provide information on the faceplate of the BC-T1. When you correlate
the descriptions in the table with the callouts in the figure, read from the top of the table to the
bottom. The standard port connector is a female DB-15.