Hi Ron, There are two "data" type services on D-STAR.
The first is part of the DV (Digital Voice) mode. The DV data stream is 4800 bps, of which 2400 bps are used for the digitally encoded voice and 1200 bps are used for FEC (Forward Error Correction) of the digitally encoded voice, this leaves about 1200 bps for other "data" to travel with the signal. They are not separate, if you are sending voice, you are sending the 1200 bps "data", if you are using the 1200 bps "data", you are also sending the 2400+1200 bps voice. The 1200 bps data section has no handshake, no error detection, no error correction (unlike AX.25 packet), think of it as a very long serial cable, but software has been developed to overcome this. One of the most actively developed pieces of software is D-RATS (http://www.d-rats.com/wiki/ ) which has an extensive feature set including many of the applications you see on packet radio. "Current Features * Instant-messaging style chat * Multiple automatic QSTs at varying schedules, containing: o Simple messages o Command output o File contents o Weather Underground reports o GPS position reports o RSS/CAP feed items * FileTransfers using DDT with adjustable-sized packets o Transparent block compression o Highly efficient binary encoding for fast file transfers, despite the limitations of D-STAR radios o Unattended operation with automatic negotiation * Online/offline status notifications * Callsign highlighting and tracking (currently supporting US and Australian calls) * Ignore capability to "dim" messages that match a search string * Notice capability to highlight messages that match a search string * Multi-platform: runs on Linux/UNIX, Windows, and MacOSX * Canned messages * Chat logging * Tabbed interface to filter traffic based on a search string * Structured data (i.e. Forms) transmission with multiple form templates, graphical editor, and HTML exporting * Form-to-Email gateway support for providing email access to distant stations * Arbitrary TCP forwarding over the RF channel * GPS position tracking, distance/direction calculation, static beacon support, and integrated map viewer with offline caching * Network-linkable repeater/proxy co-application" - From the Wiki page The second is the DD (Digital Data) mode, only available on the 23cm band using the ID-1 radio from Icom. Basically, it provides an Ethernet bridge encapsulated within D-STAR. The D-STAR gateways, provide a TCP/IP service for DD that allows you to exchange data with any other ID-1 equipped station that is associated with the gateway network. Anything that fits into the TCP/IP family of protocols and applications can be run here (within the bandwidth and amateur radio rules limitations); webservers, full email, file transfer, etc. On simplex, you can run any Ethernet protocol, such as TCP/IP, Apple talk, etc., in fact, one of the challenges is making sure your computer is not "chatty" - sending unnecessary traffic on the Ethernet as the radios will try to relay everything. DD is the network builder's "swiss army knife" if you have RF connectivity (due to the wider bandwidth, you need about 12db more path gain over a DV signal). I hope this gives you a peek as to what is possible. On Mar 26, 2009, at 8:11 AM, Ron Wright wrote: > Tom & Scott, > > I am still learning about DS and wanting to take advantage of the > digital modes. I know my question will show I know little, hi. > > I am interested in the Packet type operation of DS. That is a system > that uses a simplex one freq mode for passing info as the old analog > Packet system. Mostly used here for APRS and wx stns, but still some > comm. > > Is DD mode this, but using DStar? If so are packet modems used or is > another true non-tone digital like DS digital used? > > 73, ron, n9ee/r > > --- In dstar_digital@yahoogroups.com, "Tom Azlin, N4ZPT" <n4...@...> > wrote: > > > > Hi Scott. > > > John Hays Amateur Radio: K7VE j...@hays.org [Non-text portions of this message have been removed]
