Being able to tell the telco that you have swapped ALL of your gear and verified that your in-house demarc extension is not at fault by hooking a test router up directly to the back of the smart jack enclosure is the best path towards showing the telco the issue is on their end. If you can swap out the router, t1 wic, and patch cable to the smartjack while testing this is also a good idea. This may be the best way to convince the telco there is an actual problem. If you can take the t1 out of service, you can send a cisco ping across the line with a pattem and ask the telco to watch the line for several hours. The actual problem was a bad fiber to copper repeater that would intermittently misbehave. I have personally observed a t1 circuit that passed all basic telco pattern tests but when actual data was passed across the line, the errors would accumulate fast and the line provided only a few K of actual thruput due to the heavy errrors. You often will have to ask (demand) that the telco run longer tests, with test patterns that can simulate data transfer better.

The basic tests (sending all 1s) that a telco will do upon getting a trouble ticket do not always expose the problem very well unless the circuit is clearly damaged or a smart jack is losing singal for whole seconds at a time and the t1 is bouncing up and down. Yes, but its not as likely as the line itself still having problems. The Telco says the line is clean, but I am still having problems. There should not be any framing errors, Slips, or line code violations. show controller T1 x will give the snapshot of the T1 physical layer status. You should always check the status of the T1 controllers and verify you are not receiving any errors. You will need to ask them about the signal strength of your line is you suspect this sort of problem.īefore troubleshooting any aspect of a connectivity issue (e.g., ISDN, CAS, modem) you should always verify the physical integrity of the T1 line. The normal CO tester won't look at this sort of thing they only do the loopback pattern testing. A mismatch of clocking between our hardware and the central office crossover equipment could cause a signal to be high, such as -17db or so.

The signal strength on the t1 line should be around 0 or a few db negative. Some point to point T1's still need both CPE equipments to have clock set to line as the network provides the clock.

T1 Troubleshooting on Cisco Routers with t1 cards

Cisco receiver has remote alarm