Tech Talk- IT & Code

This blog is by Eric Tamme, member of the OnSIP Engineering Team

What is a codec?

Codec is short for “coder-decoder”. A codec is a program, or an implementation of a algorithm, which converts an analog input signal, like your voice, to a digital signal by sampling it according to the algorithm. The codec can also take a sampled stream from a matching codec, and decode the samples back to a similar analog stream that was input originally.

Here is an example codec called PCM:

Occasionally we find one of our SIP servers being probed/attacked by some joker running sipvicious. If you're on your machine and see a flood of packets that look like this:

This blog is written by Mihail Comanescu, member of the engineering team

I have been working on implementing a JavaScript IVR in FreeSWITCH and, after checking the FreeSWITCH Wiki, I found that there wasn't much information on how to do that properly. Here are some of the challenges I encountered and solutions that I came up with when implementing a Javascript IVR for FreeSWITCH:

Challenges

• Playing some type of audio recording

All OnSIP users can dial any SIP address for free. It has always been that way.

Someone recently suggested that we allow users to dial iNum (+883) numbers. They also suggested that we assign iNum numbers to our users. This same helpful iNum ambassador also provided us with the name a project manager at Voxbone which could help us out.

Someone else asked, "What is iNum?"

I recently gave a presentation to the NYC Cassandra meetup about how we use Cassandra at Junction Networks, and even data distribution across geographically dispersed datacenters using Cassandra and NetworkTopologyStrategy. This post is a overview of the presentation material. Slides from the presentation are available as a PDF from at http://files.meetup.com/1794037/NTS_presentation.pdf

I'm told that the marketing department is always looking for blog posts on something, so I figured I'd try to start posting about some ways that I use GIT. These certainly aren't brain buster techniques, but they may be helpful to the GIT novices of the world. I'll try to keep the posts to stuff that you could never do with SVN, using GIT though, that leaves the possibilities endless.

We received a comment on a recent blog post that asked us why we have implemented our music on hold (MOH) service in the manner we did. While reading the comment I realized that we released the service and alerted customers it existed, but nobody in the engineering department stepped up to explain any of the technical details behind the mechanisms we decided to support - by nobody I mean me... oops.

From "Cloud Computing" on Wikipedia...

A recent comment on Leo's stand alone VoIP service post brought up a topic always worth exploring; SIP security. Here's the quote:

There are many ways of playing video content on your website, the easiest being embedding youtube videos on your website with their copy/paste code. Another way to display a movie is to use Quicktime Player by simply calling a .mov file within HTML code. We chose to use Flowplayer for our video needs.