Monday, July 28, 2008

rtpdir bridge

The rtpdir bridge - to bridge EchoLink, IRLP, D-Star and Asterisk by Scott, KI4LKF

This group was set up to host the RtpDir bridge software(Real Time Protocol Director).

RtpDir is a VoIP software for Amateur(ham) operators. It can also be used on other bands, Government, commercial and private nets, or direct user to user without any radios connected.

If a band requires an FCC license, it is the responsibility of the end-user to obtain one. rtpDir runs on Linux or Windows platforms. NEW FEATURE: *Asterisk*/app_rpt PBX interface. There are 3 versions: Linux GUI, Windows GUI, Linux(text mode).

It can be used on the Amateur bands, Government, commercial and private nets,
or direct user to user without any radios connected.
If a band requires an FCC license, it is the responsibility of the end-user to obtain one.

3 versions: Linux GUI, Windows GUI, Linux (text mode).
To download, click on "Files".

Basic features:

Bridges and RX/TX from/to D-Star, Asterisk/app_rpt, IRLP, Echolink, Speak-Freely.
Create and operate your own private VoIP net.
Full-featured IRLP and Echolink node(link, repeater, ...).
Multiple Asterisk, Echolink nodes are accepted even when an IRLP node is connected.

Basic features:

* Runs as Echolink/Echolink conference, IRLP reflector/Echolink conference, Echolink+IRLP, private net.
* Accepts *Asterisk*/app_rpt connections
* Can transmit to *Asterisk*,IRLP,Echolink using computer mic or radio
* Graphical environment.
* DTMF control from Windows or Linux
* Control your Asterisk nodes directly using IRLP DTMFs.
* Control your IRLP node directly using Asterisk DTMFs
* Remote text command control using ssh/Linux or PuTTY/Windows.
* Can TX/RX IRLP messages without the IRLP board.
* Any station can connect to rtpDir bridge. It does not have to be IRLP or Echolink
* GSM, ADPCM, LINEAR codecs are supported.
* Protocol conversion between IRLP, Echolink and *Asterisk*/app_rpt
* ADPCM, u-Law, GSM, AMBE(with DVSI chip) codec transcoders included.
* Protocol conversion between D-Star, Asterisk/app_rpt, IRLP, Echolink, Speak-Freely.
* DTMF processing internal(built-in) or External(hardware).
* Morse code IDs or Voice.
* COS "sensing" or VOX or both.
* Support for all link interfaces(sound mode or ASCII mode, VA3TO, WB2REM, G3VFP, G4CDY,...Rigblasters, MFJ, SignalLink,...)
* No need to buy the Asterisk URI board or modify a USB sound fob.
* No need to buy the IRLP board.
* Mark a station as "Mute", "Deaf" or "Mute and Deaf".
* Timeouts for login, download, connection.
* Activity reporting.
* Audio recording and playback.
* RF station identification(audio, CW).
* Welcome message(audio, CW or text).
* Recording, playback and controlled announcements.
* Convert text to CW.
* Runs as server or client.
* Interfaces with external scripts.
* Runs with or without a soundcard.
* Audio signal strength indicator.

Tuesday, July 15, 2008

Communications in the 21st Century

Ten years ago the FCC drafted a strategic plan for High Speed Multi-Media Communications in the 21st Century. Not surprisingly they described electronic commerce growth for both daily tasks like shopping or banking and for interaction with “institutions” for education, voting, tax filing and healthcare.

They identified six “critical goals” in this competitive climate from its statutory mandates:

Promote competition — Local telephony is identified as the last major market area where competition has yet to take hold.

Deregulate — As competition develops, the FCC must reduce or eliminate regulation to the minimum necessary level to protect the public interest.

Protect consumers — The FCC states that it will have “zero tolerance” for consumer fraud such as slamming and cramming. Other areas it will remain active in are obscene and indecent programming, consumer privacy and greater ease in filing consumer complaints, as well as greater speed in responding to those complaints.

Bring communications services and technology to every American — All Americans should have access to new communications technologies. Universal service, including availability and affordability of service to rural areas, schools and libraries, healthcare providers, low-income persons and the disabled, is required by law. Yet, this must be done in a manner compatible and consistent with competition.

Foster innovation — In this area, the FCC states its goals as promoting the development and deployment of high-speed internet, promoting compatibility of digital video technologies with existing equipment and encouraging more efficient use of the radio spectrum to permit the expanding uses being developed.

Advance competitive goals worldwide — Through the World Trade Organization and other international organizations, the FCC will assist other nations develop competitive strategies, create growth opportunities abroad for U.S. companies, and promote fair
spectrum use by all countries.

So were does ham radio fit into this? Honestly I'd not even sure we are relevant when I look at our current capabilities. It's like sending a horse and buggy to transport stranded motorists.

A new ARRL field day promotional video mentions "It's not your grandfathers radio anymore..." While its good to change how people think, the reality is while the radios might have changed and look modern, their capabilities are really pretty much the same as what my grandfather might have been able to do if he was in the hobby.

Non-amateur organizations are recognizing the value of Amateur Radio. But the true value of amateur radio lies in the spectrum, or in what we could be doing. Most non-amateurs realize this.

Just as I have wrote before heeding the warning; use it or loose it, that deregulation issue comes into play. Most of our bands are on a shared basis with other services. Pay attention to the increased unlicensed use on those bands.

So what can we do to get back on track? First off; understanding vulnerabilities of the 21st century communications model is key.

When the internet was emerging it was actually a lot of separate networks that have since merged. Banking/ATM data was on their own network, now most of it is transferred over the internet. The same goes even with land-line phone calls. On just about any out of area call you place, chances are high that your phone call propagated over the internet at some point.

What we have is kind of scary with internet reliance, it seems like the eggs all in one basket approach. But there are a lot of safeguards compared to 10 years ago too. BGP smart routers that can alternatively route traffic based on network congestion, etc.

Wireless User Groups, have popped up in most large cities mostly composed (sadly) of non-ham enthusiasts. They setup Wireless community networks, using off the shelf Wi-Fi hardware communicating in the license free ISM bands. It's never to late to start something like this in your ham club. I highly encourage the formation of a back-up segregated HSMM network.

Other things hams can do were more on the technical end, spelled out in the FCC's notes. Promoting compatibility, encouraging more efficient use of the radio spectrum, and fostering innovation. Those are some of the key concepts that I try to promote in this blog. For example; D-Star/P25 digital voice compatibility solutions are an area a few select hams are working on, and I applaud their efforts.

Monday, July 14, 2008

Two-Tone Pager Decoding Using Multimon

Here is a handy Linux based project that I recently worked on for a friend who happens to be a volunteer fire fighter.

A lot of rural volunteer fire departments still rely on the Motorola two-tone sequential paging system and analog Motorola Minitor pagers for dispatching their crews to a fire scene. The standard "Motorola Quick Call 2" paging protocol consists of playing two separate audio tones, the "A" and "B" tone. The "A" tone is played first for one second, then the "B" tone for three seconds. Both of these tones are transmitted on the fire dispatch frequency (VHF usually) which the pager is tuned to. Inside the older Minitor pagers, a mechanical reed is used to filter and decode each of the proper tones. While this may sound primitive, it is actually very reliable. A modern tweak to this type of paging system would be for the fire dispatch page to also be sent to your computer or cellular phone via text or email message. That is what this project will attempt to cover, with the pager tone decoding being done in software instead of having to tie up an additional pager.

For the tone decoding software, I used a slightly modified version of Thomas Sailer's multimon Linux radio transmission decoder.

{Update 2013}
Someone forked the original Multimon.  The original version was badly in need of updating for compatibility with modern Linux installs.  The fork is called multimonNG.

In addition to showing how to modify the source code to match the tone sequences you want to monitor, there is a patch to enable a "quiet output" option to the DTMF decoding and also flushes stdout for better reliability when used in this application. A potential Perl script to trigger an external commands such as start recording or send a text message/email to ones phone is included.

You can read more about the specifics here.

Wednesday, July 2, 2008

High Speed Multi-Media using Ubiquiti

This comes from David Josephson, WA6NMF about the New Ubiquiti access point/bridge/CPE:

It can't get much cheaper than this. Ubiquiti has started shipping its "NanoStation" radios in 2.4 and 5 GHz. With the appropriate country code selected, the 5 GHz unit will cover the entire amateur allocation 5660-5925 MHz, not just the ISM/UNII frequencies. Even the 2 G.4 GHz version is capable of operations in the 2.3 GHz amateur portions of the band. 5, 10 and 20 MHz wide channels, Atheros chipset, 400 mW radio, 802.11a protocols, in a molded weatherproof case with 13 dBi antenna, dual polarization, plus external SMA antenna connector, entirely open source firmware available in an all-in-one SDK for free which you can alter and compile yourself. With power-over- ethernet injector and 12 volt wall wart, $79 for 2.4 GHz or $89 for 5 GHz.

With DD-WRT v24 rapidly nearing completion we are proud to present support for all Ubiquiti devices (LS2, LS5, NS2, NS5, PS2, PS5) for the latest release candidate RC7. The associated firmware versions are part of the line of DD-WRT firmwares for professional use. Ubiquiti offers affordable yet powerful devices based on Atheros wireless technology and allows high performance long range Wireless LAN connections, especially when driven by DD-WRT.