atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services T1's, CSU's and DSU's T1 QRSS pattern fails

I'm testing a T1 I checked configuration both sides are set up ESF B8ZS. The only pattern that fails the test is the QRSS pattern. I know this is not much info to go by but might make the QRSS pattern fail (taking errors) and all the other patterns pass( all zero, all ones, 3in24)
Thanks

Matt

are you getting pattern and frame sync? What errors are you getting? You running to a loopback or straight away? Are you running through a CSU?

Isn't 3in24 the same as Quasi (QRSS?)

QRSS is sending just enough 1's to make 1's density. The idea is to stress span repeaters.

All 1's stress the repeaters, quasi is suppose to be the most like a live random signal.

thanks for the reply:)
I actually work for the costumer I was trying to avoid going out there:) I guess they ran every pattern in the world to a physical loop on the dsx panel and the only pattern that failed was qrss. I wanted them to try 55octet which i think is very stresful pattern:) I also think all ones should give me enough proof to say that ds1 is good. I was wondering why qrss fails to a dsx bantem loop

We always found that a failure in QRS was the result of a hardware problem - Could be a bad DSX, but I would check the x-connects - look for a shiner or nicked conductor.

Sam

Also if the circuit is of any length and they are running to a DSX jack and not through a CSU they are doubling the circuit length. A CSU regenerates the signal coming back to you. To a hard loop before the csu is not a valid test, believe it or not, but try to convince most people of that though. This is something I've seen more than once and when working for the big boys made a couple customer visits where they couldn't run one or more patterns, but we always tested good. We would have them pull their hard loop and loop up the CSU and cut it through to them and they could run fine. It's right in any CSU manual I've seen that the signal is regenerated on a CSU loop back. That's what the CSU is for, to clean up and regenerate the signal. Now if you tell me they are going through the CSU I typed all this for nothing.

:bang: Sorry for all that, computer freaked.

Bill,

You didn’t type in vein, I always seem to learn something… retaining the lesson is the hard part.

jimmyv

you definetely didn't type in vein. They don't have a CSU on this ckt yet. I have a dsx panel at one location it's wired to a mutliplexer(3 feet) from there there's electrical/optical interface (OC3) and than it goes out on fiber to cust prem where there's also optical/electrical interface (T1 cards) and drops to dsx panel(3 feet from the optical box) I checked all xcnts and everything seems to be ok. Maybe next step is to move the ckt to a different T1 location:)

You could either run straight away test set to test set, or put one test set in repeat or lpbk mode to simulate a CSU. I'm betting that's all the problem is.