atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services T1's, CSU's and DSU's Adtran CSU ACE Complete waste of money. It does Nothing!

Does anyone think that Adtran CSU ACE is a total and complete waste of money and is completely useless piece of equipment?


1. Its extremely expensive for a cheaply made piece of equipment.
2. Its not necessary because the phone system does not even need this piece to run. Just plug the T1 directly into the PBX's T1 card slot and it run fine.
3. The T1 facility card will tell you if it a network loss or equipment loss. So what is the point on a CSU ace?

If you PBX are not 50 feet away from the T1 circuit, is a CSU ACE just a waste of money? Do most people not even bother with the Adtran CSU Ace in front of their PBX system’s T1 card?

Please let me know.

Thanks.

Hmmm, been using them for years and they are very inexpensive and work well for the job they are required to serve.

They are indeed useful for "balancing" the line AND offer a piece of equipment between the telco and the T1 card for testing and protection.

I think the first 2 answer the third question, and by code where I am you have to have one and rightly so IMHO.

You are required by law to have one?

Can you let me know the difference between running a system with a CSU ACE and without a CSU ace? (even if your PBX is next to the T1 circuit?

Many other phone installers have kind of shrugged them off saying " Ugh, just plug the T1 line in and it works fine without them"

So you are saying they are necessary and required by law to have? All your customers have them?

Please let me know.

Thanks.

Yep. Of course I could plug the T1 straight into the smartjack and have to test if I have a bad CSU. Yep, they are required here and every one of my customers has one if they have a digital cicuit. They don't cost alot and most my system are in the 10's of thousands of dollars. The CSU is well worth it's cost IMHO.

The CSU, in my opinion, serves two purposes. First, it takes the hit and hopefully saves the T1 card in the PBX, sort of a sacrificial lamb. Second, it does provide a test point beyond the smartjack. If the distance is short (<133', the first LBO change on most CSU's) you don't technically *need* the CSU for any real reason. Many of the vendors I work with don't use them.

A CSU is required for line protection, LBO and as a test point. It's most important job is to provide "ones density" also known as "zero-code suppression". T1 network regulations allow only 15 consecutive zeros and a minimum average one's density of 12.5%. An idle T1 is mostly streaming zeros. When the one's density drops below 12.5% T1 repeaters start to loose there timing causing frame slips and possible loss of frame sync. When you loose frame sync you drop calls. The CSU is the piece of equipment that provides the ones density requirement. On an AMI circuit it is normally referred to as "bit stuffing", "Jam bit 7" or simply "zero-code suppression". On a B8zs circuit it is called-- you guessed it "B8Zs" (Binary 8 zero-code substitution). Another clear channel code is ZBTSI. B8ZS and ZBTSI provide the ability to transmit zeros for data while continuing to meet the zero-code network requirement.

Yes, Your t1 will turn-up and run with out an external CSU. Many T1 cards in PBX's have internal CSU's, so don't require and external CSU. With no CSU on the line you are prone to frame slips and loss of sync. If the local telco finds trouble on their t1 spans because of a lack of a customer provided CSU could give them cause to disconnect the t1 until rectified.

Your Adtran CSU may look useless, but it provides a critical function in the t1 network.

So from what you’re saying the CSU ACE is not a sales gimmick but a real valuable piece of equipment.

Its just that the CSU ACE cost about 50% of the price of the T1 card in the PBX phone system. So if you buy 2 of them, it’s the same price as buying a spare T1 card in case one did blow out.

Let me ask you, how do you know if your T1 card has a built-in CSU ACE? Is there anyway to tell? Do you know which companies have this build in CSU ACE in the T1 card?

Thanks.

"Its just that the CSU ACE cost about 50% of the price of the T1 card in the PBX phone system."

That would be a very cheap T1/PRI card and probably in more need of a CSU. ACE CSU are dirt cheap compared to Kentrox CSU.

You can pick up used Ace's for about $75. Whether your T-1 card has a built in CSU depends on the manufactor. Nortel does. Some Avaya cards do. I can't speak for any of the others.

It's not a built in CSU ACE. Just a CSU. CSU stands for Customer Service Unit or Channel Service Unit, depending who you talk to. ACE is a product name. Look in the programming set-up for your T1 card and look for CSU emulation or something similar. The CSU provides protection to the network also.