Sipura SPA-3102

Summary: What a pile of utter tripe

After suffering from X100P? + modem for caller ID for a year I finally bit the bullet and bought the successor to SP3000 - the SP3102.

I was expecting it to work out of the box which of course it did not. It is was shipped with extremely old and buggy firmware which had a sour excuse for a SIP stack that did not compute the md5 hashes on the digest correctly. In addition to that it did not have support for BT caller ID and quite a few other things were broken.

I initially blamed asterisk and more specifically this bug. Applying all patches to asterisk did not get me anywhere so I went down the "upgrade firmware" route instead. What I did not realise at the time that Linksys does not keep up with non-USA firmware release trains and while UK was still sitting at the same buggy 3.x version I got initially, US was at 5+. So I downloaded the USA 5.1.1(GW) from the Linksys website. This fixed the authentication bug as well as the Caller ID. This also brought a number of other entertaining bugs. While Sipura has never been known for being particularly bug-free it is now clearly a Cisco company - for every new feature there is a bug or a quirk or two to deal with. As far as I can see:

• The echo suppression is completely broken. It must be turned off otherwise the voice distortion is completely unacceptable. It is also enabled by default which means that the default voice quality is horrible.

• I suspect that sipura makes use of the jitter buffer (or its sizing parameters) for echo cancellation. There seems to be some relationship between the two. Not documented anywhere.

• The 370+620||310nF UK impedance values have now disappeared from the Regional menu (not surprising for USA-only firmware). So there is no way to get the Line1 port to work for a UK phone at all (the PSTN Line still works). Essentially, this means that you need SIP phone(s), an asterisk (or another SIP PBX) and/or Sipura 2100 for use as stations. This also means that any Joe Average trying to use the device as originally intended will never be able to make it work and will end up throwing in the towel.In addition to that it is unclear if this value should be set for network side values which in the UK is 300+1000||220nF or for user side which is 370+620||310nF. Neither one of these is present as a choice anyway.

While it looked like it worked with the UK settings, the echo cancellation was horrible (in a hindsight this probably was due to an impedance mismatch). While it works barely enough to get you around normal calls you can forget trying to attend a conference call wit it. Your leg of the call will flood the conference with noise, echo and make it impossible for everyone else to attend. Hence, while I did not fancy shelling more money on the system I dropped the Sipura into the "spares" box and replaced it with a TDM400P? for more than a year.

I have now moved my servers into their new "home" under the staircase in the new house extension. However, I forgot about the PBX needs and ran only cat5 to there and no phone lines. So here I am using the SPA3102 to handle the legacy phone line yet again. It works after a fashion:

• I have "downgraded" it using the latest UK firmware: 3.2.10(GW), UK impedance values are now back in the menus.
• I have managed to get the echo cancellation to a tolerable level after a lot of trial and error.

Overall it is a classic example why we should all "thank" British Telecom for the wonders of the BT analogue line standards. As they are way off compared to the rest of the world, it is not surprising that most telephony hardware does not operate properly on a BT line.