Connecting PSTN line to SPA112 2-Port Phone Adapter

[b.tiru.naidu]

Hi,

Not sure if this question is right but can I use the SPA112 2-Port Phone Adapter to connect a PSTN line?  What I want is, I should be able to choose a line and while making calls.  Use PSTN or VOIP.  

Please let me know if I am using a wrong device for my purpose.

Regards,

Naidu

[tibij@cisco]

I think you are saying you have a POTS/PSTN line currently installed at your location that you want to connect the SPA 112.  The SPA does not perform that function.  The SPA is an ATA (Analog Telephone Adapter) used to connect non VOIP devices to VOIP networks.   To connect your phone system to the local lines a "Gateway" is the connection which allows your VOIP system to connect to the local POTS/PSTN lines.  But if you have a VOIP service provider they can do that as well.  I would expect you want the POTS/PSTN local lines for a backup in the event of internet connectivity outages/issues.

[Zach S]

Naidu,

To piggyback on what Jim said. If you are trying to send some calls over VoIP and some over PTSN, then what you would need is indeed a gateway. You also a need a routing plan that will fit your purposes. If you want certain numbers to go out to the PSTN and some to go out via VoIP then that is accomplished by making routing patterns, e.g. if you want every dialed number that starts with 9 to go out to the PSTN, then you would possibly use the pattern 9*.

If you are planning to use PSTN as a backup in the event that your VoIP connection fails, then that would be a different implementation.

Here's a link to an explanation on call routing, it's for CUCM 8.6, but the same basic principles apply to most call gateways:
http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/8_6_1/ccmsys/accm-861-cm/a03rp.html#pgfId-1056007