Monthly Archives: September 2009

Revisiting A GSM Interface For Your Asterisk Server

Some time ago @Boxdog pointed me to a uCPBX in Bulgaria. They are reselling various small Asterisk systems based upon the Astfin project. They have a few variations on the IP04, including an 8 port variant (IP08 = 8 FXOs) as well as 1 or 4 port BRI capable versions.

ucpbx-astfin-br4-back

The design of the base system supports adding interface ports through the use of little daughter cards. I believe that their daughter cards are compatible with Digium’s TDM-400P card. The cards even use the standard DAHDI driver making installation especially easy.

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GIPS Comments On G.722

Not long ago Dr. Jan Linden, V.P. Of Engineering at GIPS, wrote a really good blog post called G.722 Revisited. In it he considers the trend toward the use of G.722 in the rollout of new wideband telephony projects.

Dr. Linden collected a nice stable of facts in making his points regarding the use of G.722. It’s simply old and less than optimal for use over IP networks. It’s not as bandwidth efficient as many of the new codecs, resulting is lower call quality for a given data-rate. He points to a 2007 study of ITU standard wideband codecs that is quite clear that G.722 is back-of-the-pack from a pure performance perspective.

The post is a great collection of information and he is absolutely correct in making all of his points. But I think that there may be more to it than the argument he lays out, strong though it may be.

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Aswath Rao On Why Trapezoidal VoIP Is Evil!

alt_vvx1500_2_1This week’s VUC call sure is timely for me! VoIP pioneer Aswath Rao will be walking us through the evil that is “trapezoidal VoIP.” His words, not mine.

Why is this extra timely for me? Well, I spent considerable time today dealing with the very trapezoid in question. My forthcoming review of the Polycom VVX-1500 Business Media Phone has gone to the publisher for a final polish. With the text in their hands my task turned to producing the supporting images, sound files, etc that they might want to run. This time around they want to run a recorded video clip example of the what you see on the VVX LCD screen. It’s a good idea, but as it happens, not so easily done.

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My First Month With The Sprint Mifi Service

sprint_mifi_2200_2-432x479It’s just over a month since I took the decision to buy Sprint’s 3G mobile internet service using a Mifi device. Thus far I’m really enjoying the device and the service.

During my first trip with the device I racked up 1.5 GB of data transfer and was starting to worry that 5GB a month was going to be too little. But then I had two trips to Canada where the roaming fees made using the Mifi impractical. So in the first month I used around 2 GB. Not too bad.

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