confusion over srst

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Oct 29th, 2009
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hi, I am new to this so please bear with me. We currently have a satellite office setup with an mgcp gateway where the pri is located at our main office. We want to add srst capabilities to this gateway which means I need an analog line ran to the router. My question is does the analog line have to go into an FXO or an FXS port on the router or could it go into either. Could someone please explain this to me.

Thanks

Linda

Correct Answer by James Hawkins about 7 years 8 months ago

When you configure a directory number assigned to an IP phone there is a "Call Forward Unregistered" setting that allows CUCM to forward the call if the phone is not visible on the network as would be the case with a WAN failure between the offices.


If you assign the number assigned to the remote office FXO line as the Call Forward Unregistered destination then calls to that phone will be redirected over the PSTN to the remote office.


You have already identified the main issue with this in that only one call is supported per FXO line.


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Rob Huffman Thu, 10/29/2009 - 11:06
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Hi Linda,


No worries :) In your example the Analog Trunk would term on an FXO Port;




http://www.cisco.com/en/US/prod/collateral/voicesw/ps6788/vcallcon/ps2169/prod_qas0900aecd8028d113.html




Cisco Unified SRST System Administrator Guide


http://www.cisco.com/en/US/docs/voice_ip_comm/cusrst/admin/srst/configuration/guide/srstsa.html



Hope this helps!

Rob



linda0055 Thu, 10/29/2009 - 11:51
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Ok, that helped, but now I have two more questions. If we are only using one FXO port does this mean we only have one line to dial in/out on (I'm thinking like a home LAN line, if a call is on that line you cannot make another inbound or outbound call until that line is freed up). Also since our main company phone number is sitting on a PRI which is at a different site how will we get incoming calls if the WAN connectivity is broke? I see where on the FXO port I can configure an attendant DN and set it up for both ways. Is that how I would resolve this issue or would we not be able to recieve inbound calls until the WAN connection is restored?


Volodymyr Morskyy Thu, 10/29/2009 - 12:16
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As to FXO you're right no inbound or outbound call until that line is freed up.


As to PRI calls in case of WAN failure - you can reroute call using PSTN, so the call will be placed to your branch through FXO mentioned above. Just configure hunt group and hunt list and place that hunt list in the Route pattern that routes call to your branch gateway.

Correct Answer
James Hawkins Thu, 10/29/2009 - 12:56
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When you configure a directory number assigned to an IP phone there is a "Call Forward Unregistered" setting that allows CUCM to forward the call if the phone is not visible on the network as would be the case with a WAN failure between the offices.


If you assign the number assigned to the remote office FXO line as the Call Forward Unregistered destination then calls to that phone will be redirected over the PSTN to the remote office.


You have already identified the main issue with this in that only one call is supported per FXO line.


Please rate if helpful.

linda0055 Fri, 10/30/2009 - 07:39
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Actually something just occurred to me about this. If our main PRI is at another location and the link between this location and ours was broke but the PRI was still up and functioning wouldn't the main number still work, but would just go to voicemail instead of ringing the phones if I didnt have a forward set on it?


thanks,

Linda

Volodymyr Morskyy Thu, 10/29/2009 - 11:49
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FXO is for Foreign Exchange Office.

FXS is for Foreign Exchange Station(end device like analog phone or fax)

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