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New Member

IP telephony and FXS cards

I am trying to implement IP telephony solution at head office using CISCO call manager and IP telephones.

But the branch offices have FXS interfaces to connect with branch analog phones.

How do I interface these branch phones with head office IP telephony system ?


Head office- IP telephones with CISCO

Call manager.

Branches- routers with FXS and analog


Can Call manager manage remote POTS

dial peeers ?


Re: IP telephony and FXS cards

There are various options.

1. have the remote gateway added to the call manager as H323

endpoint and create a route-pattern specific to the remote fxs port configuration say the remote number 7221 and 7222. you can add

a dialplan or route-pattern as 722X and attach it to a the h323 gateway route.

the gateway voip dial-peer would have call manager address as session target.

2. you can use mgcp to control the remote fxs port and the would be seen as local endpoint of the call manager. If the phones on the remote side goes off-hook, dialtone playing would be instructed by the call mamanger.

this is supported for vg200, c2600 and c3600 only.

New Member

Re: IP telephony and FXS cards

I would suggest using the MGCP option if you can. With MGCP you can define a DN (in call manager) for the fxs port, which will allow you to CFB and CFNA to voicemail, as well as all of the other functionality a regular DN gives. If you use h.323, this is not an option.

You should also look at the ATA-186, it is fairly cheap and can support 2 analog phones.

New Member

Re: IP telephony and FXS cards

You can set up the remote routers as H323 Gateways in call manager or as an MGCP controlled gateway in call manager. Either way the analog phones can be configured. In H323 you configure dial peers in the remote routers. Pots dial peers for the analog phone ports and Voip dial peers pointing to call manager at the host site. In MGCP you configure a dial peer in the remote router for each voiceport and simply tell the voiceport that it is controlled by the MGCP app within call manager. Then you configure the remote analog phones from call manager. Look at dial peers as voice static routes. They tell the gateway how to route a call based on the dialed number.

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