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

Thanks.I had seen all the numbers before but did not see how they fit together. There was a time when all T1's had a CSU. I never got a good answer as to why they were needed because we would by-pass them on trouble when they were bad and the switch would come up.

When I worked on T1 cable spans they had the 130v on them and nothing to speak of on the cust side. Does that mean the early ones had 130v going into CSU or was it always stripped out before hand-off to the CSU?

The key is the code. Let me see if I get it.

Most orders these days are for 04ds9 NCI. That explain why you don't see CSU's much anymore. Assuming this is what my CLEC orders, he falls in the 655' category. If I tried to order it as 04du9, it would allow for a CSU but may not mate well with 04sds9 interfaces.

I'll go back to them to see what they order.

That may be why the extenders are on the market. They may comply in the latter.

While we are not on this subject, Do you know the difference between CO fail: TIA-547a and TR62411.
Does that have anything to do with CO equip/testers to access to testing, maybe past the CSU. I have been leaving this set to the former for years on Norstars.

To further explain this T1, they call it Dynamic.They have a Cisco IAX that acts as a channel bank to strip out the FAX channels/lines. The rest is voip voice and data, which I guess is all data to the T1. I am guessing a LIU is all it will have. Any suggestions for 3000' mixed 24/22. As you know, we can't get the telco to move past the demarc anymore. This is on a horse farm, and has a private 100pr the last half mile. I hate to add an additional point of failure like an extension kit.

I’m going to go backwards a lil’ bit on Field Ops explanation of NCI coding…

In the “protocol code filed” of the NCI code (position 3&4) there’s a possibility of common the “DS” and “DU.” “DS” literally is translated from Telcodia’s Carrier Coding Guide in to “Digital Hierarchy Interface” I always further translate that closer to English as a MUX, channel back etc. In other words, something that takes a signal up or down the digital hierarchal levels. Now, “DU” literally translates per Telcordia to “Digital Access Interface” which I always equate to something of an “access point” to the Telco’s digital network. A place for an end-user/customer to plug-in to the network, to over simplify a little bit for the sake of explanation.

The NCI I see the most at end-user location by far and away is: 04DU9.1SN
4-wire interface … DU= Digital interface (see above) … 9=100ohm IMPEDANCE … 1SN=1.544 Mb, ESF/B8ZS, "no line-power."

Unless something has changed they are a require interface. Some switches have a CSU built into their T-1 pack. I haven't put in a T-1 in a very long time so this requirement may have changed, but if so I haven't heard it did.

CnGRacin.

You are correct with regards to the DS NCI protocol of DS. It is generally found at the output of a MUX, since a MUX low speed card, like the channel bank or PBX LIU, is designed for a DSX-1 type interface with a fixed ZERO dB loss value.

DS NCI codes are typically found at an IC or CLEC POP location.

The DU protocol is used on about all traditional digital interfaces that represent a customer hand-off with no fixed loss values.

For example, 04DU5 is the base NCI code for DDS services. The DU NCI protocols signifies a repeated digital line interface that is engineered by the LEC not exceed a particular loss depending on service.

Some common examples;

DDS:

No more than 32dB of loss at the NI measured @ Nyquist (The DDS Data rate divided by two) from the LEC. ZERO dB from the DDS CSU.

DS1:

No more than 16.5dB towards the CPE from the LEC at the NI, and no more than 5dB of loss from the CPE towards the LEC at the NI.

Just Bill,

I agree, PBX trunk cards do include a CSU designation on card version. However I have also discovered that in some Lucent PBX interface modules the trunk card will not regenerate the T1 signal into the card, and requires the use of an external T1 CSU to accomplish the regen task.

The above PBX cards will typically respond to a T1 CSU loopback to perform testing, but that's all.

The current line of HDSL & T1 NIU's being deployed today by most LEC's will resolve any of the regen issues I have seen in the past. Unless the PBX is situated far away from the LEC NI equipment.

If the magic was too easy, then there would be no need for technicians to do any work!!!

Good Telephone Karma for all.

The Inter-Tel systems I use do not require an external CSU/DSU. It is built into the T1 card.

Come to think of it so do the Norstars(built in CSU).I had thought is was for testing, but it does have a line build out.

This Cisco IAX is built for Nuvox, the CLEC may not have any regen, although I hear the Call Manager switch has an internal CSU

NuVox uses the Cisco 2431 & 2432 series IADs. It's a typical channelbank, except the whole T1 is setup for data and voice calls are sent over IP.

You're looking at maximum of 655 feet from the ILEC DEMARC, just like virtually every other channelbank.

You're going to need a repeater or T1 extender if the install will be 3Kft from the ILEC DEMARC. Adtran makes a device to extend a T1, and requires one on each end of the extension. I know a technician who has a T1 extended close to a mile with this setup.

Thanks Kyle, something the cust won't be glad to hear because it isn't in their quote. The one in place is going to a Carrier Access Device (Adelphia/Telcove)channel bank, and it does not use one(extender) but it must have the ability to regenerate the signal. I guess from wht you say I won't have that same luxury with the Cisco.

NuVox should install their equipment a few days before the actual cutover. They call it a plant test date. Have a DEMARC extension in place for the technician to connect to. Give it a try and see what happens. The worst case scenario is you push out your service activation date a week or so while you order extenders.

That's what I was thinking. I know they hate that, but I told the salesman it was 3k, just in case it mattered.This is Windstream, former Verizon, former GTE where this is going in. If I get a tech from one of the formers, they will try any settings they can to help. The new local is more "Bell like".(this is what you ordered, this is what you get, if you don't like it, you need to re-order.) I am going to try to be there for their install date too.

Splitting Atoms.
As Filed ops provided, there are ways to order that could give me the boost, but yet be incompatible :shrug: