[aprssig] Android can do analog APRS on 144.39
Stephen H. Smith
wa8lmf2 at aol.com
Thu Mar 28 12:10:42 CDT 2013
On 3/28/2013 12:50 PM, Georg Lukas wrote:
> Hey Tom,
> * Tom Hayward <esarfl at gmail.com> [2013-03-28 17:14]:
>> The D72 has two data ports:
>> - The USB device port enumerates as a serial port and offers memory
>> programming, CAT, and raw TNC access.
>> - The 2.5mm COM port offers NMEA GPS input and waypoint output.
> I was not aware of the two separate ports, as I do not have a D72.
Actually, the port arrangement is nearly identical to the TH-D7; i.e. one
serial port for the TNC to communicate with the PC, and a second serial port
for the GPS to communicate with the radio's built-in TNC.
The only major difference is that the radio<-->PC interface has been
converted to USB inside the D72 to accommodate modern "legacy free" PCs that
lack serial ports, but that do have USB. This is done with the same sort of
chip that is used in stand-alone serial<-->USB cable dongles.
Annoyingly, Kenwood opted NOT to use the common Prolific or FTDI serial<-->USB
chips, whose drivers are very likely already on most systems. Instead Kenwood
used the far less common Silicon Labs CP210x "USB to UART Bridge" chip.
As with external serial<-->USB dongles, you have to install a driver on the
PC that recreates a virtual serial port that then communicates with standard
serial-port-oriented APRS programs. (Ironically, even Kenwood's own memory
management program for the D72 still expects a SERIAL port, either virtual or
real, rather than natively using the D72's USB interface.)
When under the control of a PC, the GPS data sent into the (real) GPS serial
port on the D72 is echoed out the (virtual) serial port to the PC, just as on
the earlier TH-D7. When you use an EXTERNAL GPS on the D72 (but not it's
built-in one), the (real) GPS serial port can echo received posits from the TNC
as NMEA waypoints back to the GPS for display if it has one. I.e. you can use
both the GPS and the map in an AVmap, Street Pilot, Nuvi 350, etc.
Stephen H. Smith wa8lmf (at) aol.com
Home Page: http://wa8lmf.net
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