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PRI for PSTN

cstewart
Level 1
Level 1

I am in process of setting up my phone system and had some questions for you who have worked with PRI's before. I am using an HDV module in a 3640. I am planning on having 2 pri's. I am in the process of ordering the pri's and had some questions on the settings of the pri's.

1. Should the protol for the pri be national or

custom.

2. If national, then FAS or NFAS?

3. # of digits outpulsed by CO

I have been told that cisco equip. supports national or custom but I wanted to know what someone who has done this reccomends... Thanks.

6 Replies 6

mschlenger
Level 3
Level 3

IOS supports most major PRI protocols. You need to get this information from telco. (ie, what kind of switch will you be connecting to...what is the protocol they will be emulating) Typically, CO's send you the last 4 digits of any given DID # dialed. You have to look at your dialing plan and request what the CO gives you. So if 630.555.1212 is dialed, you can expect the CO to deliver 1212 to the gateway. I would certainly confirm this with telco. Hope this helps.

thanks for your reply... do you have any experience w/ nfas? Do you recommend doing this?

NFAS is ok on IOS gateways. It is not currently supported on WS-X6608-T1 and DT-24+. If you are going to have 2 t1's it will save you 1 timeslot. I have configured it on IOS gateways and it does work. So that is really up to you.

Thank you,

So the 2621 as a VoIP gateway can do NFAS. I thiugh it was just the 3600 seris routers.

They can both definitely do NFAS for ISDN data. But for NFAS using ISDN voice I know the AS5300 can do it, but if the 2600/3600 is able to do it, then it is pretty recent. If you are not particular about this point then you should probably ask for FAS (D channel on each PRI) to be safe. Also, go ahead and ask for national protocol.

Thanks for the help guys....

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