Date: Tue, 20 Nov 2007 16:36:37 +0000
From: wb6ymh
Subject: [Repeater-Builder] "thelinkbox" beta testers wanted (OT)

I'm looking for Beta testers for my new VoIP software project called "thelinkbox". The code has been running pretty well for a while now, but the documentation is still minimal and sketchy. If you would like to help test the code and documentation drop me a private email and I'll put you on the beta list.

This project is not intended for Linux or radio novices, it's intended to appeal to those that like to "play with the bits" and "push the envelope".

The eventual public release announcement will read something like this:

Thelinkbox is a voice over IP (VoIP) radio linking package for ham radio operators that runs under FreeBSD and Linux, and hopefully other Posix compatible operating systems.

Although the primary purpose is for VoIP linking of a limited number of repeaters "off grid", i.e. separate from the EchoLink and IRLP networks it can also be used on Echolink if desired. It can not be used on the IRLP network.

Unlike other systems thelinkbox also supports multiple radio ports.  The ultimate goal is for thelinkbox to become a full featured multiport hub or repeater controller as well as a VoIP application. I believe the use of USB audio dongles under Linux will allow a modern PC to support a larger number of radio ports than are likely to be needed by even the largest repeater groups (> 16 ports), although I have yet to test this theory in practice. I'm currently running 2 RF ports, but I will be adding more ports in the future.

Here are some features:

1. Support for multiple simultaneous connections using different codecs and protocols. Currently tlb supports ADPCM and GSM codecs and the Echolink, RTP, and Speak freely protocols. When multiple sources are active the audio is mixed. 

2. The number of VoIP connections is only limited by system RAM and available bandwidth.

3. Support for up to 32 physical radio ports (assuming OS and hardware support and enough processing power).

4. All ports are completely independent: Each port may have a unique set of DTMF commands. Each port can be connected to a distinct VoIP clients.

5. A full cross point matrix of connections between VoIP clients and RF ports is supported.

6. Does not require the user of a central server or authentication authority, all that is required is internet connectivity. 

7. Support for either prerecorded PCM audio announcements or external text to speech systems such as Festival.

8. CW and voice IDs.

9. An audio sweep tone generator for system testing.

10. "Permanent" connections, if a link is lost tlb will keep trying to reconnect indefinitely.

11. Software DTMF decoder 

12. Open source software written in C and C++.

13. Support for inexpensive USB audio dongles including PTT and COS sense.

14. Software driven CTCSS generation and decoding.

Currently tlb runs on FreeBSD or Linux and supports serial port based Echolink interface boxes and rigblaster style interfaces. Under Linux the IRLP parallel port interface and modified iMic USB audio dongles are also supported. Thelinkbox does not (and probably never will) run on Windoze.

I've been running the code on and off for the last couple of years.  K7KAJ, and N7LF have been running the code and helping me test for the last several of months. So far we've tested the code on FreeBSD ver 4.9, FreeBSD 6.2, and Fedora Core 5.

The first beta release of thelinkbox is primarily useful as an EchoLink "sysop" client. Although it can be used independently of EchoLink reasonable authentication has yet to be added.

I've created a Yahoo group for thelinkbox @ for discussions about the project and to avoid polluting this list with off topic discussions.

Also see for a wiki documentation and installation instructions.

73's Skip WB6YMH


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