e s0/1 Module type is T1/fractional Configuring T1s Hardware revision is 0.112, Software revision is 0.2, Image checksum is 0x73D70058, Protocol revision is 0.1 Transmitter is sending remote alarm. Receiver has loss of frame, Framing is ESF, Line Code is B8ZS, Current clock source is line, Fraction has 24 timeslots (64 Kbits/sec each), Net bandwidth is 1536 Kbits/sec. Last user loopback performed: dte loopback duration 08:40:48 Last module self-test (done at startup) Passed Last clearing of alarm counters 08:45:16 loss of signal 1, last occurred 08:45:07 loss of frame 2, current duration 00:01:38 AIS alarm Remote alarm Module access errors Total Data (last 34 15 minute intervals): 2 Line Code Violations, 0 Path Code Violations 1 Slip Secs, 200 Fr Loss Secs, 2 Line Err Secs, 0 Degraded Mins 0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 200 Unavail Secs Data in current interval (896 seconds elapsed): 255 Line Code Violations, 255 Path Code Violations 32 Slip Secs, 109 Fr Loss Secs, 34 Line Err Secs, 0 Degraded Mins 0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 116 Unavail Secs Here, we can see that the CSU/DSU is sending a remote alarm (yellow alarm) out the T1 because it's receiving loss-of-frame errors. More importantly, one loss-of-signal event occurred approximately 8 hours and 45 minutes ago. This T1 has not been up since the router booted. The last time the alarm stats were cleared was also 8 hours and 45 minutes ago. This output essentially tells us that there's nothing on the other side of our circuit. Sure enough, the router on the far end is powered off. It also has an integrated CSU/DSU. After we power up the far-end router, let's clear the counters and see how the service module looks: Router#clear counters s0/1 Clear "show interface" counters on this interface [confirm] 09:00:04: %CLEAR-5-COUNTERS: Clear counter on interface Serial0/1 by console Router# Router#sho service-module s0/1 Module type is T1/fractional Hardware revision is 0.112, Software revision is 0.2, Image checksum is