atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services T1's, CSU's and DSU's DS3?

Today, someone asked me if I could extend a 'DS3' from their buildings network interface. This is a circuit for a cellular service provider. Is this the same thing as a T3? And furthermore, how is the wiring for a T3 different from that of a T1? I was told a 'DS3' is a four-wire circuit. Is it the same as T1 (pins 1/2 and 4/5)?

The only DS3's I have encountered around here have been coax cable. My experience with these may be limited, so don't count on my being 100% correct here. We were hired by a national service company to extend one and couldn't do it because we didn't have the correct cable and termination tooling.

Yes it's the same as a T3. If copper it would be 4wire, just as a T1 is 4wire on copper. It's the carrier signal that's different. Just in case you didn't know there are 28 T1's on a T3. I'm not sure about pin out, I've only seen hard wired. I would think it would be like any other modular connection though.

Should have phrased it a T3 can carry 28 T1's

Bill
you mean 28 T1's on a DS3 right?
T3 is 3 T's (3 x 1.54)

Guess it's my old AT&T terminology. To me a T3 is the system, DS3 is the jack on the T3. The way I understand DS3 means the same as T3. I've never heard the term T3 used as 3 T1's, but there's lots of terms I've learned on this board different from what was used by AT&T. When we lost a T3 carrying T1's we lost 28 T1's. Now there was an older carrier that was T2 or DS2, I don't remember how many T's it carried. :confused:

Think of it like this. The "T" in T1 or T3 is transport, the physical layer. The "DS" in DS1 or DS3 is digital signaling. "T" is the water hose, and "DS" is the water flowing through it. In the industry, the terms are commonly used interchangeably.

So far as I know, DS3's ride coax only. I don't believe it's possible to extend a DS3 over twisted pair.

DS2 is valid, although you'll never see it. It is used inside multiplexers only. It's 4 DS1's. Seven DS2's make up a DS3.

I have never messed with a T3 (DS3) on cust prem. So I bow to Kyle's expertise. I knew that ol' transport thing Kyle, didn't even enter my mind. Thanks for the help.

Forgot to mention, I do know there were 4 T1's on a low speed card, but never heard it call T2.

Kyle is nails on...
DS3=Digital Signal level 3 (logical) = T3 Transmission level 3 or Technology level 3 (physical) depending on who you speak with.
A DS3 is also the equivalent of a STS1 Less the SONET over head and an STS1 (synchronous transmission signal)is the electrical equivalent of an OC1(optical carrier).

DS2= 4 DS1's. And I too, have only seen them on "low speed cards" in an M13 mux. They are pretty much only a logical entity. That’s probably why I don’t recall ever hearing them referred to as T2’s either.

As far as extending it, you need to use coax cable with BNC's (Bayonet Neil Connectors) only. Do not try to use "F-type" connectors that you would use for cable TV. However, RG6 cable should do just fine (two runs, one transmit the other receive). When extending it don't forget to check the line build out or you may run bit errors even if the cable is okay. You are better to over drive the signal a little, if in doubt.
Good luck! DS3’s are actually very easy to work with. Even easier if you have the proper tools and test equipment.

PS.
Don’t forget, 672 DS0’s ride a DS3 (24-channels on a DS1 times 28 DS1’s on a DS3=672 DS0’s (lines)). So, don’t unplug it at 4PM when everybody is making their last calls of the day or you’ll make lots of enemies.

Turns out the building has a contract with a company for riser management and installations. Oh well, thanks for the info - good to know anyways.

A Building LEC,, heard about them, never seen one.