sundance-communications.com/forum Forums Wiring - Telecom Carriers - Trunks & Services T1's, CSU's and DSU's T-bird and T-1 questions

I am just curious. Can someone give me a good explanation of the difference between slips and misframes as it pertains to a T-1?

Slips is a timing issue, with a T-berd (or any other test set) you have to clock off a known good clock source to see slips.

OOF errors are cause by repeaters usually.

Slips are pure you won't see anything but slips, no other errors. High OOF's may also cause slips, but the trouble is OOF not slips.

True pure slips can only be CPE trouble with very rare exceptions. No one no matter how good they are can test for slips with just one circuit, no matter how much some LEC's will tell you otherwise. If the LEC tells you they looped up a circuit and see slips, just roll your eyes and walk away.

You can and will have a completely error free T-1 if you have bad timing but the T-1 still won't work reliably.

That's about the best I can do.

Is a "TBERT" the same thing as a "T-BIRD? As in "Bit Error Rate Test" set?

I'm just asking. I have never understood the phrase "T-Bird" until I Googled it and realized that this is yet another trade-specific misnomer. Wow, I learn more every day. I am now wondering how many people laughed at me behind my back for it!

I had always thought that this was just a brand name given to a piece of test equipment (and it probably was) that is now the industry norm. Sorry for the side-track on the subject.

It's actually T-BERD, manufactured by TTC which was purchased by Acterna, and is now owned by JDSU I believe.

Make sure the test set is configured for recovered timing. Depending on the model, this can be pretty intuitive (like on the 2209 touchscreen series), or a bit of a pain on the older sets (like the 224).

Yes..I am guilty of using slang... I will slap myself silly.... wait, my wife already does that.. :rofl:

Want to add when a PBX or CSU reports slips on a private point to point T-1 it would be true because on the master end they are the clock source. Again though it would be a CPE issue if slips were seen.

For you to see slips on a point to point T-1 the customer would have to have two point to points and you'd have to time your T-1 test set off one and test the other.

Don't have any concern, we all laugh behind your back...the same as everyone else laughs behind our back.

JDSU is now the company that manufactures T-Berd test equipment.

The "classic" test sets (209, 211, 224...etc) are all discontinued because the company is focusing on high bandwidth/optical test equipment (GiG-E, FE and so on).

JDSU/Acterna same thing. The new test sets can break out DS0's and test them. Test T1's and test them and DS3's. If you have the right one you can test also test optical. They all support some sort of computer based interaction as well as interchangable modules for upgrading the unit to test up the OC N chain