stuff.... random stuff....

SPA3102 no echo out of the box

, posted: 16-Nov-2007 16:07

This week i have been playing with a Linksys SPA3102.

Linksys SPA3102
Linksys SPA3102

I have installed one of these in Kaitaia so my mother is on my asterisk system. I figure that if I can set up VoIP for her (without her knowing it of course) and she is able to use it, then it’s pretty much fit for anyone! All she does is pick up the phone and make calls as per usual. The dial sting in the SPA3102 then works out if it should route the call via her POTS line or via VoIP. She calls Australia a lot so I route any calls to Oz via

The Device

I have used the old SPA3000 and found them good, however the SPA3102 is much better. For a start there is no echo on the PSTN/POTS line out of the box! Although I was able to tune the echo out of the SPA3000 it was nice have this just work.

Ring Thru

The ring thru feature allows incoming POTS calls to call the connected extension rather than routing the call out the DSL to the Asterisk server and back again! this feature is very handy, however it took me a while to get going. If you find that it does not work for no apparent reason (no syslog errors either) then you will probably find that you have set different preferred codec’s for Line 1 and the PSTN Line. Or you have set ‘use preferred codec only’ to be incompatible between the 2 lines

Strange inbound ringing

While utilising “ring thru” I have noticed that it sometimes takes a while for the phone (connected to LINE1) to stop ringing after the calling party has hung up. This ‘may’ be something to do with regional settings. I have been a bit slack and have not checked and set them all yet. I will do that tonight to see if it makes a difference.

Audio Level

As per usual on these devices you will have to tweak the audio level to get it right. I found it fine on Line 1, but a little bit low on the PSTN side of things.

Life Line

Like the SPA3000 in the event of a power failure, the SPA3102 features a ‘life line’ which connects the POTS/PSTN line together. This is great for my Kaitaia installation as the power is often doggy.


This device is not an ‘easy’ device to get right however it sure is better than the SPA-3000! Once you have it set you can forget it and it will simply keep on working. For the price, the unit provides excellent audio on all the codecs it supports (I have been using ulaw and g729).    

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chris021's profile

Chris Hoffmann
New Zealand

Areas of Interest:
Network Security
Computer Forensics


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