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New Contributor

CRC errors recorded on endpoint equipment

Hi,

I have a T1 CSU ACE in place between the telco's smartjack and our endpoint equipment, which happens to be a Brooktrout TR1034 fax board. I actually picked up the T1 CSU ACE specifically because we were seeing quite a few CRC errors recorded by the card (among some other issues, telco-related), and were hoping it would clear them up. We inserted the T1 CSU ACE and had the telco do an hour-long loopback test to it (which they swear they did) and they were unable to record any errors on the circuit whatsoever. In the meantime, we are still accumulating errors on the endpoint device.

Any thoughts about this so far? Should we still be seeing CRC errors on our endpoint, even if it's only a couple of feet from the CSU (shouldn't that eliminate CRC errors?)

This is the kind of frequency/timing we're talking about (from the TR1034's log):

06/10 02:07:59.98 ECC {2,A} < CRC error detected

06/10 02:17:36.99 ECC {2,A} < CRC error detected

06/10 02:36:35.00 ECC {2,A} < CRC error detected

06/10 02:41:57.50 ECC {2,A} < CRC error detected

06/10 02:44:35.50 ECC {2,A} < CRC error detected

06/10 02:54:08.00 ECC {2,A} < CRC error detected

06/10 03:15:53.02 ECC {2,A} < CRC error detected

06/10 04:06:23.55 ECC {2,A} < CRC error detected

06/10 05:22:52.59 ECC {2,A} < CRC error detected

06/10 05:45:06.10 ECC {2,A} < CRC error detected

06/10 05:51:09.60 ECC {2,A} < CRC error detected

06/10 09:02:43.20 ECC {2,A} < CRC error detected

06/10 09:09:18.70 ECC {2,A} < CRC error detected

06/10 09:35:17.73 ECC {2,A} < CRC error detected

06/10 09:54:02.73 ECC {2,A} < CRC error detected

06/10 10:06:48.24 ECC {2,A} < CRC error detected

06/10 13:42:32.85 ECC {2,A} < CRC error detected

06/10 13:56:51.36 ECC {2,A} < CRC error detected

06/10 14:01:44.36 ECC {2,A} < CRC error detected

06/10 14:22:55.87 ECC {2,A} < CRC error detected

06/10 14:30:57.37 ECC {2,A} < CRC error detected

06/10 14:39:15.88 ECC {2,A} < CRC error detected

06/10 16:03:01.92 ECC {2,A} < CRC error detected

06/10 16:57:35.94 ECC {2,A} < CRC error detected

06/10 17:22:57.46 ECC {2,A} < CRC error detected

06/10 17:23:10.96 ECC {2,A} < CRC error detected

06/10 17:32:22.47 ECC {2,A} < CRC error detected

06/10 20:11:04.04 ECC {2,A} < CRC error detected

06/11 02:07:01.26 ECC {2,A} < CRC error detected

06/11 02:14:06.26 ECC {2,A} < CRC error detected

06/11 02:16:25.76 ECC {2,A} < CRC error detected

06/11 03:09:07.79 ECC {2,A} < CRC error detected

06/11 04:44:07.34 ECC {2,A} < CRC error detected

06/11 04:55:07.35 ECC {2,A} < CRC error detected

06/11 07:24:05.65 ECC {2,A} < CRC error detected

06/11 07:30:27.68 ECC {2,A} < CRC error detected

06/11 07:32:59.18 ECC {2,A} < CRC error detected

06/11 08:01:20.26 ECC {2,A} < CRC error detected

06/11 09:49:56.16 ECC {2,A} < CRC error detected

06/11 10:37:27.82 ECC {2,A} < CRC error detected

06/11 11:00:20.35 ECC {2,A} < CRC error detected

06/11 11:35:02.47 ECC {2,A} < CRC error detected

06/11 12:17:28.61 ECC {2,A} < CRC error detected

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2 Replies
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New Contributor

Re: CRC errors recorded on endpoint equipment

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Valued Contributor
Valued Contributor

Re: CRC errors recorded on endpoint equipment

Yes, the T1 CSU ACE should eliminate any errors your
equipment receives from the Smart Jack. Make sure the T1 CSU ACE is set to 0-133
feet (or whatever the appropriate distance setting is). You may try setting the
line length on the T1 CSU ACE to -7.5 dB (an undocumented setting with switches
3, 4, and 5 in the UP position - in case the signal is too strong for your end
device). If your end equipment is still showing CRC errors then try changing
out the T1 cable from the T1 CSU ACE to the end device.

Does your equipment still show CRC errors to a T1 loopback?
You can do an “equipment loopback” on the T1 CSU ACE by putting switch 7 in the
UP position. I would also suggest using a T1 loopback plug.