TIARA Technology [a.k.a. Asterisk/app_rpt project]
The integration of 2-way radio systems and reasonable telephony
WHAT IS IT?
TIARA Technology is a Radio Over VOIP application which runs on the Asterisk PBX and provides a way to link multiple radio systems together using Voice Over IP. app_rpt/Asterisk and all the underlying software to make it happen has recently been renamed "TIARA Technology". The architecture of TIARA technology allows for quite a bit of flexibility and freedom:
- The software is an open-source project licensed under the GPL. This means you get the source code and can make any modifications you wish provided you make your modifications available to the community.
- Multiple hardware interfaces supported one of which is the Quad Radio PCI card
- No central authority for authorizing connections. You are free to use ours, or set up a your own completely isolated network of systems.
- All of the security features in Asterisk are at your disposal (Public/Private keys, IP address filtering) plus, a DNS-based authentication method to handle Internet connections with dynamic IP addresses using dynamic DNS.
- The ability to remotely execute a DTMF command on any node from any other node.
- Have multiple repeaters interfaced at one site while only running one instance of app_rpt and Asterisk on one computer. Repeaters can be in the same or different groups so that you can have, for example, Amateur and GMRS repeaters controlled by the same computer but set up in a way that they can never be interconnected.
- app_rpt is a repeater controller, not just a voice gateway.
- app_rpt and Asterisk can run on a Mini-ITX embedded PC powered off of 13.8VDC using Limey Linux and a Compact Flash Boot Device.
- Autopatch, and Reverse Autopatch over traditional landlines or through a VOIP service provider. VOX-based or full duplex.
- VHF/UHF remote base operation using the Doug Hall RBI-1, TM-271A, or Kenwood TMG-707A
- HF remote base operation using the Yeasu FT-897 or ICOM IC-706 all-mode radios.
- Secure remote base access using individual user logins to prevent unauthorized access.
- Ad-hoc connectivity. Any node can connect with any other node. Any number of nodes can connect to a node (subject to bandwidth limitations).
- IAX2/ ADPCM (g726aal2) uses 55 kilobits of bandwidth. Optionally, GSM may be employed to reduce the bandwidth to 35 kilobits.
- Audio connections in the digital domain to rtpDir through the use of the chan_rtpdir Asterisk channel driver
- Control and access to the radio via dialup
- iaxRPT soft dispatch console
- Facilities to integrate with existing addressable full duplex RF linked systems.
And much more...
Native support for Echolink using the chan_echolink channel driver without having to install rtpdir! For more information click here
FAQ
MAILING LIST
A mailing list for discussion about using TIARA technology is available here
PROJECT GOALS
The main goal of TIARA technology is to provide an open-source repeater controller that is as inexpensive as possible while being as agile and featureful as is possible.
We certainly haven't invented the repeater controller, but we have certainly implemented it in a new and different way, which has allowed for new and improved features to be implemented that would not otherwise be possible.
The advantage that our system design gives is the creative use of VOIP (Voice Over Internet Protocol). This is not the first use of VOIP for radio systems, but it certainly is the first one that is both open source, and implemented a sensible and efficient manner (in the realm of repeater networks).
A nodal approach is used, whereby using VOIP, a connection can be made between nodes, thus allowing repeater to repeater linking or remote base operation from a repeater. The example below illustrates the concept:
The example above has 4 radio systems located over a wide geographical area. Each radio site has its own node ID, and each radio site can connect to any other site in the system without using a centrally located server. In other words, each node is autonomous and does not rely on a central point of authority (Unlike other implementations).
Even in areas where systems might be in radio-contact distance of each other, using the Internet for linking is less expensive and more versatile then traditional UHF radio techniques. In addition, it makes all nodes accessible from anywhere desired.
Although not shown in the above diagram, Remote Base nodes can also be present in the system. The way we implemented the remote base node allows for independent operation from its "repeater" host. In fact, there doesn't even have to be a repeater running on a system (just 1 or more Remote Bases). In a traditional configuration, 1 or more remote bases are hard-tied into a local repeater system (which potentially could be linked-to). To use that remote base, you must either be on or linked to that repeater system, thus requiring the repeater system to be tied-up if some link user wants to use its remote base. In our architecture, there is no such thing as hard-tying any node to any other node. For example, a system might contain 1 repeater and 1 remote base system (say nodes 123 and 124). Because they are not hard-tied, the repeater system (node 123) and the Remote Base (node 124) are completely independent (autonomous) of each other. One user can be using the repeater, and another user may connect to the remote base use it while the repeater is in use.
SYSTEM IMPLEMENTATION
A system consists of a PC running the Linux operating system and the open-source Asterisk PBX telephony switching system. The TIARA technology Asterisk application, app_rpt.c, comes bundled in the release of Asterisk, however we also maintain our own source code repository containing the latest version of app_rpt.c and its support files.
In addition you need a QRV Communications LLC PCI Quad Radio Interface card, a DMK Engineering URI, or a modified USB sound fob.
For each node, a process (well, thread actually) runs on the Asterisk server which runs our Asterisk application (app_rpt.c). The thread manages all of the repeater functions, and implements all of the DTMF control functions, linking, remote base, and interface to inbound and outbound VOIP channels. If you are interested in seeing some of the internal functionality and architecture of app_rpt, check this out.
NETWORK PLANNING
Unlike other architectures, TIARA technology allows implementation of your own network in any physical configuration and node numeration scheme you desire. There is no assumption made, or requirement that you be part of a global, open network.
If you wish to do so however, there are two public "node assignment authorities":
2. PTT Link For commercial (e.g. GMRS, and PMR446)
You can also conceive of and organize your own private or public node assignment authority if that is what you want.
RADIO INTERFACES
There are 2 radio interfaces available which are compatible with TIARA technology
2. The URI (Universal Radio Interface. Supplied and supported by DMK Engineering)
This is a 4 port radio interface card, called the "Quad Radio PCI Card":
. 
Rev. B Production version of Quad Radio PCI Card.
The PCI quad radio card plugs into a PCI slot in your computer, and has interfaces for 4 radio systems. Each interface port includes a full CTCSS (and DCS) subaudible tone decoder and encoder, as well as all of the features necessary to interface your radios (repeaters) with Asterisk.
SOURCE CODE
TIARA TECHNOLOGY DOCUMENTATION
A short write up on how to set up Allstar link node registration can be found here
A short write up on how to use the automatic node update feature for Allstar Link is located here
A glossary of terms is located here
CONFIGURATION EXAMPLES
The Initial set of configuration files for one working channel can be downloaded from here. The are 4 common files, and
subdirectories for each type of interface. Download the common files, and the files for the interface you are using.
All configuration files go into /etc/asterisk except zaptel.conf which needs to go in /etc.
The rpt.conf.sample configuration sample file contains documentation for every configuration option in app_rpt.c. This file is not intended to be used as is for configuring your system. It is intended as a reference for each configuration option and a guide to how each option is used. rpt.conf.sample can be viewed or downloaded from here
Various configuration examples can be seen here
Yaesu FT-897 menu settings for an app_rpt frequency-agile remote base
SOUND FILES
Additional sound files are required to ensure app_rpt voice prompts are properly sent.
The app_rpt sound file tarball can be downloaded from here. These are voice recordings app_rpt needs to send command confirmations and other voice messages. This file is unpacked into /var/lib/asterisk/sounds. When it is unpacked, it will create an rpt directory and place all the sound files in there.
CABLE DRAWINGS
These are cable drawings for interfacing the Yeasu FT-897 and Icom IC-706 All-mode HF-UHF radios and a Kenwood TMG-707 dual band radio as a frequency agile remote base. These drawings are only suitable for applications where a user wants a frequency-agile remote base, and are not intended to be used as a node radio. Node radios are interfaced much more simply as no external circuitry is usually required.
LINKS with additional information
IAXRPT - A soft dispatch console for app_rpt
Limey Linux - A small linux distribution tailored for Asterisk and app_rpt for Via Mini-ITX PC's
ACID Allstar Centos Installation Disk. An automatic install of Centos, app_rpt, and Asterisk for Allstar Link
SolarPC - Mini-ITX computer system which runs off of 12VDC as used at some of our sites
Xipar - Xelatec IP over Amateur Radio site
LINKS with 2-way radio information
SYSTEM PICTURES
The picture below is our "3 repeaters in a suitcase" demo system. We demonstrated app-rpt at Astricon 2005 with this setup.
Some more pictures of our installations can be found here.
CONTACT
Steve Rodgers, WA6ZFT
The app_rpt Asterisk application was conceived and designed by Jim Dixon, WB6NIL, and has had major contributions and help from Steve Rodgers, WA6ZFT. The Quad Radio PCI card was designed by Jim Dixon with help from Steve Rodgers, WA6ZFT,and David Kramer.
