D-Star Open  Source / Dextra project  by Scott Lawson, KI4LKF  

His D-Star work spawned from his rtpdir bridge project of 2008.

http://sourceforge.net/projects/ircddb/files/ by ki4lkf (November 2010)

The D-Star implementations of his project have moved around many times and he discontinued his work briefly from April 2010 to November 2010.  But much can be learned from his code.  

He coded the first Open D-Star G2 gateway + repeater.  As well as first open source GMSK node adapter repeater / hotspot software.
DSTAR G2 Gwy and DSTAR rptr with GMSK RF: register a DSTAR rptr, DSTAR routing, link to Reflectors, DSTAR local RF/GMSK, TRUST server updates.
It runs as a D STAR G2 Gwy/Rptr not like a fake like Dplus hotspot.

The repeater can run on Linux or Windows.  The G2 Gateway runs on Linux.

Some Background:

While the D-STAR specification does use a proprietary vocoder (AMBE), the actual specification (for on air) is open (though you need to be able to read Japanese for the full specification), as developed by the Japanese Amateur Radio League (JARL).

All of the non-air protocol callsign routing functionality of the Icom proprietary gateway software, as well as the proprietary D-Plus add-on have all since been reverse engineered, and mostly all by Scott.

The AMBE chip can be bought in single quantities from DVSI for $20, or one can use the DV Dongle developed by Robin, AA4RC, and Moe, AE4JY. or the new DVSI USB 3K

There is an open source replacement codec in development called codec2, being developed by David, VK5DGR and endorsed by Bruce Perins, K5BP.  However this is expected to be incompatible with the AMBE codec chip in the Icom Radios.  An interesting open source Digital Speech decoder program does decode some DVSI codec's, but does also have some possible patent infringements as this time.

It should be noted there were some personality clashes in his development efforts.  Scott's development/testing methodology differed greatly from those of the USTrust/K5TIT and the D-Star add-on Dplus by AA4RC.  Both USTRUST and Dplus teams are focused on reliability and stability of their TRUST.

Dextra was a response to DPLUS, Scott wanted to ride on DPLUS (interoperate), but a feud exploded between the two authors.  

However there are also portions of the community that have different needs and requirements.  Scott filled that need by creating Dplus replacement tools like Dextra, and a whole splinter experimentally minded D-Star network (using his open source G2 gateway code) called the multi-trust, which has its own reflectors based on his system called DExtra. It's similar to DPlus but with a completely open protocol. It includes D-Star repeaters using sound cards connected to radios as well as the GMSK node adapter.

His software, network and footwork encourages development of homebrew hardware and software solutions and aims to give developers a network to connect their systems to which has fewer restrictions.

Not being able to connect in at the D-Plus layer led Scott to investigate connecting at a G2 Gateway layer.  Discovering that callsign routing updates were sometimes taking upto 2 hours, and the closed nature of the Icom/USTRUST/K5TIT trust prompted him to write his Open G2.  An open source replacement to the $300 ICOM RS-RP2-G2 D-Star repeater gateway software.

This led to the development of X-Trust/Multi-Trust Network.  The Xtrust network which is centered on activity in Germany and other parts of Europe.  This network is expanding rapidly.

The X-Trust/Multi-Trust system uses a distributed architecture, using multiple Trust Servers which have synchronized databases, each Trust Server then supports the gateways in the usual G2 form. Users can connect using G2 routing throughout the X-Trust/Multi-Trust network in the normal way, as far as the end user is concerned there is no difference.

In the summer of 2010 a team of enterprising German hams released a D-STAR Gateway add-on software package that allows callsign routing to function between US-TRUST and non-TRUST users.  The Java software uses “irc” (Internet Relay Chat) protocol to share data.  US-TRUST has given the “OK” for implementation and testing of ircDDB on Gateways within the USTRUST network.  ircDDB enables homebrew D-Star gateways and Icom stacks to work without being attached to any trust server system and communicate with all gateways being attached to the network using callsign routing.

Each gateway that adds support for the ircDDB network, will have more reliable source routing (contacting another ham using the “YOURCALL” field).  Location updates can be delayed by relying only on the Icom/USTRUST/K5TIT trust network.  ircDDB allows gateways members to update in near real-time.

The user does not need to take any action or change any behavior to take advantage of the update.  All of the work is “behind the scenes”.  It does make callsign routing more valuable, since subscribing Gateways can track the last repeater a user accessed with almost no delay.

http://ircddb.net/ For more information and a list of subscribing Gateways.  There is an English language explanation available in the links on the left of the home-page.

http://download.ircddb.net/tools/dextra_ng/ For support to connect to XFR conference reflectors

http://www.va3uv.com/Vulnerability.htm - A very interesting observation about D-Plus.


Miscellaneous Archived KI4LKF Software:

rptr_v2.93_Linux.zip - DSTAR Repeater for GMSK Modems 

open_G2_srv.tgz - OpenG2 Gateway that can accept one of the following as repeater controller: rptr/GMSK modem repeater by KI4LKF & DG1HT, or the ICOM RP2C repeater controller hardware, or Jonathan, G4KLX's sound FOB repeater program plus board.


mux.tgz - version 1.14 - rptr_mux (Repeater Multiplexer)  acts as the intermediary between Icom G2 and the home brew system.  It multiplexes repeater bands A,B,C of only one repeater
under one G2 Gateway. It does the same job as the ICOM RP2C repeater controler, but it does it in software only.

dplus_client_win.zip - package for connecting to the D-STAR/dplus network with a DV Dongle

dplus_client_linux-3.4.zip -  package for connecting to the D-STAR/dplus network with a DV Dongle

D_STAR_Open_Source-Files-Hot-Point-10-05-09.rar -The D-Star Hot Point software converts your radio station to a dstar RF gateway. It uses your d-star dongle, an analog base radio and a radio interface like a rigblaster, VA3TO, or ULI, signalLink or WB2REM or any USB interface board or RASCAL,...

The software will use RTS or DTR to key up the base radio. For COS, the software will try to detect CTS or DSR or CD. (Instead of COS, you can use VOX with the VOX threshold).

The basic setup is, you will have a analog base radio at your QTH attached to your computer (Linux or Windows) thru the radio interface(rigblaster,ULI board, signalLink,WB2REM,VA3TO,USB-based adapter).

Any local RF user tuned to your base radio's frequency will access the dstar network, because the dstar_hot_point software will open a connection to a remote D-Star node. You will be able to control the dstar_hot_point software and command it to disconnect or connect to any remote dstar node you want, by using DTMF tones on your HT.

Also, the dstar_hot_point software allows you to use the computer MIC and speakers if you do not want to use a radio.

chan_dstar.zip - Asterisk channel driver for D-Star. This driver requires a DV dongle to convert analog to digital audio and back

DSTAR Repeater for GMSK Modems V2.93 Windows Linux
DSTAR Gateway D-Extra (R2G2_X) V1.21 README Windows Linux
DSTAR Gateway D-Plus (R2G2_P) README Windows Linux
DSTAR Reflector List in the XREF network README

The r2g2_x and r2g2_xr are DSTAR Spot (to link to Reflectors) programs used with the DSTAR repeater software rptr/Linux or rptr_win/Windows in combination with the GMSK modem/adapter/USB device



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