Connect Branch site PBX and Head office PBX to Head Office CUCM via Voice Gateways

[ali.raza0407]

Dear all,

Currently we have a CUCM installed at head office and we have one PBX at head office and othe is at branch office. These are tradiditional PBX's and doesn't support E1. Now I want to conect these PBX's with voice gateways on trunk ports and than connect the voice gateway with CUCM on SIP trunk. Please tell me is it possibe to do that for both head office and branch PBX or not? Currently also tell me either we require only FXO ports or also FXS ports?

Best Regards,

Ali Raza

[Gajanan Pande]

Yes, its possible. For configuration documents, please checkout documents provided at following links. You have not mentioned the PBX brand but please see if you find your PBX brand integration with CUCM & Voice gateways at following links..

http://www.cisco.com/en/US/solutions/ns340/ns414/ns728/networking_solutions_products_genericcontent0900aecd805b561d.html

http://www.cisco.com/en/US/solutions/ns340/ns414/ns728/networking_solutions_products_genericcontent0900aecd805bd0e4.html

Pls rate the post if it helps.

GP.

[Maxim Denisov]

Hello Ali.

It is possible but using fxo/fxs ports you can not transmit dialed number so one side can identify dialed subscriber by port only. Fxo ports can can transmit dialed numbers and fxs can receive it.

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[ali.raza0407]

Hi Maxim,

Can you please confirm, can we only use FXO ports to connect to PBX or we also require the FXS ports. If we require both than how both will function?

Best Regards,

Ali Raza

[Maxim Denisov]

FXO ports can send dialed numbers and FXS can receive it. Let's see the scheme when you have a PBX with 100 subscribers and 100 subscribers on UCM with IP phones. If you connect the PBX to a gateway with 10 FXS ports you can address maximum 10 subscribers on PBX from UCM and the PBX subscribers can address all your UCM subscribers. For FXO ports you can address all subscribers on the PBX and 10 subscribers on the UCM.

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[ali.raza0407]

Hi Maxin,

In my scenario I have 500 users at UCM end and 300 users at PBX ends. What I understand from your reply is that if we only connect with 10 FXO ports than we can able to address all subscriber on the PBX but 10 subsriber simultanoeulsy. Also we can only able to connect to 10 UCM users and not all of 500. We should have to define the 10 specific extensions. Can we able to use both FXO and FXS ports. If we can than we could be able to access all subscribers at both ends but 20 simultaneously. Also simulateously we could able to make 20 connection in either directions. e.g 5:5,9:1 ratios if we are using both FXO and FXS ports.

Please clarify your reply.

Best Regards,

Ali Raza

[Gajanan Pande]

Ali,

To avoid such limitations, T1/E1 PRI trunks will be used to connect Gateway router & PBXes. Multiple PRI's means enough channels to accomodate simultenious communication between CUCM & PBX users.

GP.

[ali.raza0407]

Hi Gajanan,

Existing PBX doesn't support E1. Thats why we are going to connect via FXO/FXS ports. Its will be really nice if you can also reply on my last reply to Maxim. I really want to clear this scenario ASAP.

Best Regards,

Ali Raza

[Maxim Denisov]

Ali,

You understood me right. FXO always works in pair with FXS on the other side. FXO side can only receive a ring, FXS side can receive a dialed number.

Such solution is bad from the design point of view, think about upgrading your PBXes with PRI ports or moving to pure VoIP.

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[ali.raza0407]

Hi Maxim,

Thanks for your reply. Now I got your point. Now its mean that at branch office we can connect PBX with FXO/FXS and by using a SIP trunk over a IP WAN. We can conect this to the CUCM located at HO.

Best Regards,

Ali Raza