Linkbox-url
From cqinet
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What is thelinkbox?
Thelinkbox is an voice over IP (VoIP) or more correctly radio over IP (RoIP) radio linking package for ham radio operators that runs under FreeBSD and Linux, and hopefully other Posix compatible operating systems. It does not and probably never will run under Windows.
Thelinkbox is basically thebridge conferencing software with additional code to interface to radios. 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 the Echolink or IRLP networks when properly configured.
Unlike some other VoIP 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 the limit in practice.
Features
- Open source software written in C and C++.
- Support for multiple simultaneous connections using different codecs and protocols.
- ADPCM, GSM, and uLaw codecs.
- Echolink, RTP, and Speak freely (IRLP) protocols.
- Codec and protocol transcoding is supported.
- Integrated conferencing (reflector) functionality.
- Audio mixer with automatic gain control to prevent over modulation.
- Precorded PCM audio or external text to speech synthesizer for announcements.
- "Permanent" connections, if a link is lost tlb keeps trying to reconnect indefinitely.
- Software DTMF decoder.
- Support for inexpensive USB audio dongles including PTT and COS sense.
- Support for multiple connection dependent command lists.
- Flexible tone generation scripting capability.
- Multiple sinewave function generators.
- DTMF generation.
- AX25 Packet generation.
- PCM file playback.
- Audio Sweep generator.
- Flexible scripting support to allow control from Web pages, etc.
- Repeater controller functionality.
- CW and voice ID.
- Transmitter and receiver timeout timers.
- Transmitter hang time.
- Courtesy tone generation.
- DTMF muting.
- Full cross point connection matrix between physical and VoIP ports.
- Audio prioritizes for things such as monitor mute, monitor mix and monitor drop.
- Software based CTCSS generation and detection.
- Frequency and CTCSS control support for remote base radios.
- Tone burst access control for Europe.
Who is it for?
If you are a Ham who enjoys experimenting and "pressing the envelope" and feel limited by other RoIP projects the linkbox may be just what you are looking for. If on the other hand you're looking for easy to install, easy to use program you can get going in an evening, this is almost certainly not for you. Although this project is not intended for Linux novices, you're more than welcome as long as you don't mind learning.
What do I need to run it?
Thelinkbox is usually run on commodity (often old and discarded) PCs. You'll need a reasonably recent (2.6 kernel) version of Linux or FreeBSD and have software development tools installed. In order to interface your radio you'll need a sound device that supported by the operating system and I/O for COS input(s) and PTT output(s). The sound card must be a 16 bit card and support full duplex operation. The COS and PTT I/O can be connected to either serial ports, the parallel printer port, or via some USB audio devices. Some Radio Interfaces are available if you don't want to build your own.
Thelinkbox can also be run on a number of interesting low power and possibly inexpensive platforms. In general if the platform runs Linux and supports USB or has sound hardware you can probably run thelinkbox on it. You'll need a suitable compiler or cross compiler. The following platforms are of special note SheevaPlug and LittleBlue.
Does it have a GUI?
Thelinkbox itself is a *nix daemon that has no user interface component at all. In addition to user definable DTMF commands entered via a radio port tlb can be controlled using the command line utility tlbcmd. Tlbcmd can also be used to control tlb via scripts which can be used to create web pages or other means to control tlb.
Recently we have begin developing an web application for the OpenWRT platform for configuring and controlling tlb. OpenWRT-LBE (OpenWRT Little Blue Edition) includes both tlb and the web application. Currently tlb running on OpenWRT-LBE can be configured and controlled using the web interface almost exclusively. The only task that still requires you to use the command line is setting the initial audio levels using alsamixer.
How do I contact the Install team?
Walk into the nearest bathroom and look in the mirror! If you don't trust the person looking back to install tlb for you then you should probably pick a different project. That having been said specific questions posted to the thelinkbox's Yahoo group usually result in speedy replies.
Thelinkbox is intended for the Ham that enjoys getting into the low level details of Internet linking of systems, it is not intended as an turnkey appliance. With the flexibility that thelinkbox offers comes a non trivial amount of complexity. Reading tlb's documentation can be time consuming and frustrating but it will be less frustrating than trying to install and configure tlb without reading it.
