NuFone, Teliax, LNP, and Asterisk audio quality problems

Posted by Scott Laird Thu, 12 May 2005 14:11:30 GMT

Since I’ve been having problems with my Verizon POTS line, I decided that it’s finally time to look into porting my main home phone number to a VoIP service. Right now, I’m using call forwarding on the line, so all incoming calls come in via VoIP anyway; using local number portability (LNP) to move the number directly onto a VoIP service won’t really make things any less reliable, but it will save me $15 or $20 per month.

I’ve been using NuFone for most of my VoIP traffic for over a year, but they only provide local numbers in Michigan; I’m in Washington, so that’s not very useful to me. I did a bit of research, and Teliax comes highly recommended on the Asterisk-Users mailing list and they’re able to do LNP ports in my rate center. Teliax seems to be sort of a cross between full-service VoIP providers like Vonage and pre-paid wholesale providers like NuFone–they have both prepaid by-the-minute plans and monthly minutes-included plans. Even the prepaid plans include the option of having them provide voicemail; it’s not very useful to me when I have my own Asterisk server, but I like the idea of having a provider that I use that I can recommend to non-Asterisk users.

Since Teliax can provide the service that I need, I went ahead and signed up. It only took a couple minutes to enter all of my data on their website, and my new incoming number was active immediately. Their support website includes Asterisk configuration snippets, dynamically-generated with my username and password, so all I had to do was paste them into my Asterisk config files and everything worked.

The one thing that I noticed immediately was that Teliax calls sounded a lot better then NuFone calls. By default Teliax uses the GSM codec, while I had NuFone set up for ILBC. By most accounts, ILBC should sound slightly better then GSM, so I’m not really sure what’s up. I changed my NuFone settings to use GSM, and suddenly the slightly swimmy sound that I’d been hearing on NuFone calls for the past few weeks went away. I suspect that my Asterisk build has a slightly-broken ILBC codec, but I wouldn’t have noticed this if I hadn’t added a Teliax account. Since this isn’t the first time that I’ve had ILBC problems, I’m going to drop it and stick with GSM for now. If it starts bothering me too much, then I’ll consider paying $10 and licensing G.729 from Digium, but I doubt there’s any purpose in doing that.

So far, I’ve only used Teliax for about 12 hours, and I haven’t ran more then a handful of calls through them, but so far them seem great. I have Asterisk set to reject them and log a message if their ping time rises over 400ms, but it didn’t trigger overnight. If it can make it a couple days without 400ms worth of network problems, then I’ll start the process of porting my home phone number to Teliax. For now, I’m going to change the forwarding on my Verizon POTS line to point to Teliax instead of NuFone.

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Verizon's at it again--call forwarding rings busy

Posted by Scott Laird Tue, 10 May 2005 23:58:37 GMT

Verizon’s doing weird things with my home phone again. At the moment, I’m paying for call forwarding on my home line, so any time someone calls my home number, the call is forwarded to my NuFone VoIP account. This was working just fine, but I’ve received busy signals when calling home twice in the last week. Since I’m able to call home via NuFone directly without any problems, I’m assuming that the problem is on Verizon’s end.

It’s taken a bit of poking around, but I think I’ve figured out what’s happening–Verizon will only forward one call at a time. If a second caller calls while a forwarded call is in progress, then the second caller will receive a busy signal. That’s a really nasty behavior–I’ve effectively lost the ability to do call waiting and to take voicemail messasges while I’m on the phone.

Since this is clearly happening on Verizon’s end, I called their local repair line and talked to someone. In the past, I’ve had much better luck with their repair number then their sales number–the repair people have access to the switch–but this time the agent was terminally confused by this–she got mixed up and thought that I was forwarding my calls to my cell phone, and concluded that it was the cell provider’s problem. Once she got into that state, I couldn’t figure out how to un-confuse her, so I guess I’ll have to wait until tomorrow and try to get a new repair tech.

I guess I should see this as an incentive to find someplace that do a LNP port of my home number to a cheap-ish VoIP service. It looks like Teliax might be able to do it, and most people on the Asterisk-Users list seem to think highly of them.

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