atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services T1's, CSU's and DSU's Trouble shooting tips?

OK, you lost me here and I'll tell you why:

When you have a B8ZS transmission from the A-end hitting into a mux at the Z-end where the low speed card (or C card depending on the mux design) is programmed for AMI, you'll take errors and there's one pattern - I forgot whether it's 1:7 or 1:8 - that won't run. QRS will run with no issues. I've learned this the hard way...let me just add that the circuit was designed (in both cases that I've seen) as a HDSL in the field. My take would be that when the switch on the low-speed card is incorrectly set, I don't believe that the type of C card used really matters - be it a H2/H4 HDSL one or the conventional "full" T-1 card...

I'm *not* questioning your knowledge - way too green for that - just trying to understand what you were trying to say...

I think your getting deeper into theory than you need to to trouble shoot T-1 troubles.

I've only worked pure 4 wire T-1's so know nothing of this new stuff, yet the basics would still be the same.

When you are talking low speed cards you're talking about breaking a T3 down to the T1 level and I don't think that's where John's going. I do think John knows what he's talking about, but just don't think you need to be that deep into it to trouble shoot T1 problems.

The biggest problem with low speed cards, at least in my experience, is when the T3 resets, or high speed card is changed, the default is AMI on the low speed. As you know AMI won't pass B8ZS, but B8ZS will pass AMI. So why didn't they make the default B8ZS? $$$ is the only reason. They want the customer to pay for privilege of running B8ZS.

Learn the basics the hard stuff you'll pick up as you go. The vast majority of your trouble will fall into the basic category.

The only time we installed AMI was on voice-only (56K) circuits. It was explained to me at the time that because these circuits were simpler, they were also more robust, which is what voice managers wanted.

Data circuits (full 64K) ran B8ZS. Data managers wanted to be sure that the data came through immaculately.

All 1s should run on anything. All 0s will only run on B8ZS. QRS is not designed to test the data carrying capabilities of a circuit, rather it's designed to troubleshoot physical plant. When I would get failures on QRS I would look to the cross connects, the wire wraps, the patch cords, the jacks - that sort of stuff.

Like Bill I have no experience with 2 wire circuits. I would echo what he said - learn the basics and the hard stuff will come. Pay attention and take notes.

Sam

Adtran and HDSL T1's scramble the transmission such that there is never 8 zero's will never be transmitted.

"Pay attention and take notes"
There is no one for him to pay attention to or take notes from. They are all gone. Either retired or pushed out the door with Supplimental Income. His situation is typical of the modern telco technician inside and outside! They will only teach him enough to get by until such time he becomes expendale.

The subject was T1's not muxed circuits. I'm only talking about T'1s leaving his CO to a smart jack and the different techniques.

I wish I were closer to WI, because for this statement alone - all of your other contributions nonwithstanding - you earned a dinner and quite a few drinks from me...

Thanks once again - Bill, Sam and obviously John - for reminding me how much I still have to learn after a decade of doing this stuff...

To OP - good luck. Bookmark this thread and visit it often...

Keep the questions coming!

John, if the OP is running trouble on HiCaps there would be no end user. Unless the term HiCaps has changed since I retired. It's a DACS to DACS type circuit between two offices, usually a long haul and local office.

That's why he mentioned the MUX's. I doubt he even touches HDSL. We'll have to hear from him to be sure though.

From his original post:

It sounded like he wanted information from the DSX to the equipment side of the repeater, out the facility side to the cable pairs, which his responsiblity. If he wants to trouble shoot the office in he must do as you say from the low speed card channel DSX towards his mux