SPA3102 with no POTS/PSTN line


I bought an SPA3102 a while back so I could run my POTS line through asterisk. I never really got around to setting it up, but we are moving in a couple of weeks, and I thought we’d go fully VoIP.

I have already got my Asterisk box setup and working with a VoIP provider, but really like my “PSTN” phones (which are cordless) and want to still make use of them.

Will I still be able to to use the SPA3102 to just connect my “PSTN” phone with my Asterisk server? All the guides and HOWTOs that I have read on setting this device up make mention of setting up a PSTN trunk (inbound and outbound), but I won’t have a traditional landline.

In particular, I was looking at the HOWTO at, which seems to be “the” guide to setting up one of these units. Assuming that it is possible to use one of these units without a PSTN line, if I were to follow this guide, what part(s) could I ignore and what part(s) do I actually need to use this unit as just an "extension| for my "{STN"phones?

I hope this makes sense? Thanks! :slight_smile:


If you do not have a PSTN line to connect the device to, then in essence you have a single line VoIP adapter. You ignore any instructions for setting up a SPA-3000/SPA-3102 with Asterisk, and you ignore the PSTN Line settings on the device (other than perhaps to clear out the registration information so it isn’t needlessly trying to connect to your Asterisk server). Then you find instructions for setting up a Linksys PAP2 (preferably) or an SPA-2000, and use those to configure all your other tabs. You will only have one line available for use instead of two, but otherwise all the instructions are exactly the same.

Do remember to go to the SIP tab and set the RTP Packet Size to 0.020, rather than the factory preset of 0.030 which is NOT correct for use with the uLaw (G711u) codec (which is what you’ll probably use).