atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services T1's, CSU's and DSU's Fax problem caused by RX slips. (T1/Titan5500/5ESS)

It's a Carrier Access Adit 600. (I'm certainly no big fan of them) It has (2) 8 port FXS cards in it and a router card in slot 6.

Just for reference, I swapped that out with an Adtran 912 (Love adtrans, hate the tech support wait.) and still got the controlled slips.

depending on what type of OE this is built on in a 5e will determine what errors you can see. If it is on an IFAC, you will most likely not see the slips. If it is built on a NEN you will be able to see coding violations, errored seconds, severely errored seconds, severely errored frame seconds, unavailable seconds, and controlled slips

I am being told it is a NEN and we are seeing slips on the 5E interface. About 1 per 15 minute interval so I am told. We are seeing about 1 or 2 every minute and an average of 34 every 15 minutes.

to be honest it is very very rare for me to see the trouble originating from the switch, it is almost always something out towards the customer. Especially if you try to roll this to a new SM and the trouble follows. I have had similier troubles in the past, for every errored second I had, I had an identical slip, looked like a timing issue.It would often turn out to be a defective t3 card. switch it over to protect and all cleared..

1 quick way to determine if the slips are being caused by the 5E would be to compare the output of the suspect switch T1 with the output of a known good switch T1.

If the suspect and the chosen good T1 spans are both CSTs you would have to map the circuits to TAPS and connect to the monitor jacks on the DSX panels.

Sorry meant to edit not quote.

A couple of other thoughts. I’m grasping for straws. Is the 5E a host or is it a remote? If it’s a remote then there are other network elements that come in to play. Can the C.O. tech turn on the switch cutoff call report to see if it shows anything? The Plant 24 Report gives the number of switch cutoffs for the whole switch. Turning on the Switch Cutoff prints out a detail of every call that is classified as a switch cutoff. There used to be another report that you could turn on called the transient cutoff report. That could point something. Maybe there are others having a problem that you’re not aware of. I really want to hear what happens on this.

Well boys and girls...and bf6b5yr, we just got another complaint of fax troubles and it appears as though the customer has two T1s one of voice and one of data and guess what.... there are slips on the voice T1!!! Not sure if I should be happy or sad but we are doing some work to see if the customers have anything further in common.

I would start looking at this at a t3 leavel

I'm moving this to the T-1 category. Majestic, just remember one thing, the timing source can't cause slips, that should help you trouble shoot your problem. I'm not real good at T3 so I'll let anthony deal with that part. You have a timing option set wrong somewhere, that is the only thing that will cause pure slips.