Asterisk SS7 Software Radio

  • 09/01/2012 UPDATE:

  • I wrote this page back in 2005 - 2006, and am surprised at how consistent the information has been.
  • Since Software Radio / Software Defined Radio grows more powerful, due to advancements in the processing power of general purpose processors,
  • society will be able to one day have a multi-waveform handset hopefully on multi-waveform networks.
  • I'll update this page shortly with the latest developments.
  • SDRGuy

This is Software Radio: (I suggest you download this MIT .mpg file!!)

This is a 22MB .mpg video where a MIT student demonstrates handling wireless protocols, all with the signalling processing be done entirely in Software on a general purpose Intel/AMD box. :)

What is Asterisk again?


Asterisk is a complete PBX in software. It runs on Linux, BSD and OS X and provides all of the features you would expect from a PBX and more. Asterisk does voice over IP in four protocols, and can interoperate with almost all standards-based telephony equipment using relatively inexpensive hardware. <---Just like GNURadio!! ( Read below)

The benefits of using Asterisk is that it is a telephony toolbox/Kit offering a environment for such development.

In Asterisk, everything needed is close at hand:

  • SS7 - (Provided by either or via Asterisk SS7 LIBISUP)
  • T1/E1/DS3 channels
  • Call engine interfaces and status,
  • User interfaces,
But No RADIO WAVES — (Yet... Enter GNURadio ;) )

Since the SS7 LIBISUP has been implemented in software here:

Asterisk does now support SS7

After several months of live testing VoIP operation in Europe and Asia, SS7 is now available for Asterisk. The LIBISUP solution is fully integrated with Asterisk and does not require any additional external equipment.

We now know Asterisk can directly interface with the PSTN network!

In my opinion, all that is remaining for Asterisk is Radio Waves. Or the reverse is true of GNURadio, since it provides Radio Waves, all it needs is Asterisk!!!

Why cant Radio Waves be served to Asterisk in the form of software?


GNU Radio is a Free Software toolkit for learning about, building, and deploying Software Radios. Software radio or SDR - is a interesting subject where mathematical formulas become radio.


GnuRadio offers reconfigurability. Spending $1000 on a piece of radio hardware buys you access to whatever that particular radio is configured for.

If you have adequate generic GnuRadio "style" Hardware, (the same hardware you use for Asterisk), all of the radio processing can be done in software.

Currently only a few forms of radio are duplicated in GnuRadio Software, but if you understand the math of a radio transmission system, you can reconfigure your GnuRadio to receive it.

GnuRadio & Asterisk runs on Linux machines.

GNURadio is currently only tested on x86. Software Radio tends to like a lot of CPU speed because it does a lot of math. RAM is less important than CPU speed. Whereas RAM CPU speed and RAM are BOTH VERY IMPORTANT for ASTERISK on high loads of transcoding(s).

So either GNURadio integrates Asterisk into it, or Asterisk integrates into GNURadio?

2b or not 2b? That is the ? Is this not worth finding out ?! :)

As for how to get the Radio Waves into your Asterisk/GnuRadio Box, use the following external hardware:

The Universal Software Radio Peripheral (USRP) is a low-cost, high speed implementation of GnuRadio Hardware, developed by a team led by Matt Ettus.

Another method of getting raw data is to use USB-2.0 to deliver it.

Vladimir Dergachev,, was part of the team that designed the Universal Software Radio Peripheral, as well, as he designed the SR-1 Software Radio.

SR-1/Software Radio
(Man, look at what Vladimir did to that Cypress chip!!)

Overall, Software Radio was conceived by Joseph Mitola:

One of the best forms of Software Radio is that of

Vanu Bose,, took off with, what I like to call, "Vanu Style Software Radio", by conceiving of his SprockiT middleware.

SprockiT separates high-speed data flows from asynchronous control messaging. Data flows move at
predictable rates in a single direction down largely stable pipelines of modules. Data flows are implemented using receiver pull, which maximizes efficiency when receiver and sender are serialized software modules executing on the same underlying processor. Data flows are also optimized for the caches and memory hierarchy of the underlying processor by run-time selection of iteration size. In contrast, control messaging is handled out-of-band, sender-push, and is not limited to flowing down stable pipelines. This better matches the way in which control messages are used and reduces overall software complexity.

As I understand it, the Open Source version of SprockiT is GNURadio. :)

Asterisk will be complete Once it has SS7, T1/E1/DS3/etc, and Radio Waves available to it all using general purpose hardware such as Intel/Amd:

Software Radio on General-Purpose Processors

Design and Implementation of Software Radios Using a
General Purpose Processor

See more information at

Lets see what the future holds for Asterisk, SS7, and Software Radio.


Created by: SoftwareRadioGuy, Last modification: Sun 02 of Sep, 2012 (03:47 UTC) by sdrguy
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