atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services T1's, CSU's and DSU's Need some Education on PRI

Hello,

I need some assitance with understanding how a PRI works. I am trying to get pricing and information on a PRI from qwest, but the rep and I was asking about long distance and she said 'if both locations are using the Qwest PRI then the LD is free.' and I was thinking both locations? I only have one I am asking about right now. I was Trying to get more information and she said 'It's a point to point connection'. Does the PRI have to be pointed to another location physical office? isnt it pointed to qwest for phone service?

What does she mean?


I was mentioning another location we might possibly hook up with service, but I didn't give her an address for it or anything.

OK i talked to our phone tech and he clarified it with me...

The qwest rep thought I wanted a point to point PRI and what i really want is a local PRI.

I GOT It she was confusing me...

So, do you need clarification as to how a PRI works? It might be helpful if you can tell us what kind (brand and model) of phone system you have so we can give you the most accurate information.

Well we are using a meridian Northen telcm phone system.

but I stil lhave some questions about PRI. I found this discribtion of what the diffrence between a T1 vs a PRI:

"PRI or Primary Rate Interface is a switched service deliver OVER a T1 connection . If someone were to say “I want to order a PRI to location X.” What is being requested is a connection to a trunk side module capable of ISDN protocol to a Telco switch delivered to location X via a DS1 rate (T1) circuit.

Now if someone were to say “I want to order a T1 to that SAME location X.” … well… That wouldn’t be enough info… A T1 from where to where? A T1 for what? By just asking for a T1, nothing is understood or implied about where or what the circuit would be used for. A T1 can be used to truck data at the rate of 1.544 Mbps from one location to another… With channel banks and appropriate DS0 level cards, a T1 can be used to truck up to 24 separate and distinct DS0 signals (analog data, analog voice, or Digital Data Service) from one location to another… A T1 can be used to connect one location to an ISP Internet Edge device to connect a customer to the World Wide Web… In other words, a T1 is a multi use pipe…"


But the REP on the phone was talking about a point to point PRI connection between two physical locations for voice data between the two.

But can you actually do that? In the guy discription above he is saying a PRI connects using the ISDN protocal to a TELCO SWITCH Via a T1.


Can you use a PRI in both ways?

And a Voice T1 and a PRI the diffrence between the two is the protocols that are used?

Oh man my head is spinning...

With a point to point T1 you can use it for voice and/or data depending on the equipment you have at each end. They are basically just providing the "Pipe" and it is up to you what it is used for.

The thing with T1's and PRI's is it all depends on what equipment is connected to it on each end.

As quoted above, a T1 is just a 24 channel circuit that can be used for multiple things. A PRI is a protocol that uses the 24th channel to control what the other 23 channels are used for.

The features or lack of totally depend on where the circuit is going and what it is connected to on the other end.

OK....... I think I understand now... PRI is a diffrent protocol to be used with voice services over the T1 line. Were as a t1 line can also be used for voice but without using the PRI protocal and probably using diffrent equipment at the other end to get the dial tone....

Keeping it on simple terms... yep.

There are a lot more technical details dealing with ISDN lines (PRI's/BRI's) but you've got the basic idea.

Emilia, why are you requesting a PRI rather than a voice T1? What application are you using the PRI for?

well the Voice t1 is like Outragously expensive and the quotes I am geting for PRIs are going to slice our costs in half. Also, we desperatly need better CallerId options. Like sending out individual DID's on outgoing Caller ID. Plus over all PRI sounds like a better service.

Voice T1 service is frequently very expensive since you are still paying almost as much per month for the 24 lines PLUS the cost for the T1 being used to transport them to your premises.

PRI is much more economical since all channels are dynamic, in that they act in many different ways depending upon the call type being made or arriving. The rate structure for them is also much different for a PRI, meaning that there is less "head end" cost. A PRI requires less hardware on the telco end, so there is less cost for them. This, in turn is passed on to the customer.

ISDN-PRI really is the only way to address your needs, as long as your system has the capability to interact with the power of an ISDN circuit.