[aprssig] re: TM-D710A Control Program - New Goodies on D710

Stephen H. Smith wa8lmf2 at aol.com
Sat Aug 4 10:54:11 CDT 2007

John Habbinga wrote:
>> 2)    The much hyped "Echolink / VOIP" support is merely 10 memories 
>> for DTMF sequences that can be labeled and the recognition that the 
>> 6-pin MiniDIN connector can be used for voice audio as well as 
>> external TNCs, sound cards, etc.   These 10 memory slots are 
>> apparently separate from another set of "DTMF" memories.
> I'm glad to see the Echolink feature, even if its implementation is 
> rather basic.  I think that the somewhat built-in soundcard interface 
> might be useful for some other digital modes.  For example, if the TNC 
> turns out to be inadequate for regular packet, then the soundcard 
> interface could be used with AGW-Packet Engine software to run Winlink 
> email clients without the need for an additional black box between the 
> computer and the radio.  ATV applications also come to mind.

Again, this is nothing new.   Many rigs from various manufacturers have 
had the 6-pin mini-DIN "packet"/"data" connector (which is actually a 
line-level audio I/O plus squech and PTT) for years.   Recasting this 
connect as an "Echolink" interface is purely a figment of Kenwood 
marketing.  This connector has been a Japanese industry standard for 
over a decade. I have at least 4 different radios from Kenwood and Yaesu 
that implement this feature. As a sound card interface, it is deficient 
as it still lacks the transformer isolation needed to prevent ground 
loops; i.e. you will still need to use an external sound card interface.

>> 9)    "APRS/Navitra" menu (I thought Navitra, the Japanese forerunner 
>> to APRS and the original design target of the D700 was now history, 
>> but apparently it still lives.) has 6 sub-menus.
> I think the Japanese version of the D700 used NAVITRA.  Now it is just 
> built-in to radios destined for all the various markets.  Is it me, or 
> does "NAVITRA" sound like a "male enhancement" pill?

Navitra ("NAvigation TRAnsceiver") was a Japanese-only protocol somewhat 
similar to APRS.   (You can see some screen shots of Navitra on my 
website at:
     <http://wa8lmf.net/aprs>   Scroll down to the bottom of the page.

The D700 was originally developed for NAVITRA.  When the radio flopped 
in the domestic Japanese market, and when Kenwood became aware of the 
developing APRS phenomenon outside of Japan, they salvaged their design 
investment by re-doing the radio's firmware for APRS instead.   The  
insufficient buffer in the radio's TNC is a legacy of the radio being 
developed originally for a non-AX25 packet  application, and then the 
firmware being re-purposed for AX25 APRS applications without a hardware 

No doubt the vastly increased ROM space in today's mainstream 
microcontrollers, compared to the ones being used 8 or 10 years ago, 
makes it possible to have both Navitra and (vastly-enhanced) APRS in the 
same CPU.   What surprised me is that Navitra is still around. I had 
thought it basically disappeared, even in Japan, when APRS took off 


Stephen H. Smith    wa8lmf (at) aol.com
EchoLink Node:      14400    [Think bottom of the 2M band]
Home Page:          http://wa8lmf.com  --OR--   http://wa8lmf.net

NEW!   World Digipeater Map

JavAPRS Filter Port 14580 Guide

"APRS 101"  Explanation of APRS Path Selection & Digipeating

Updated "Rev H" APRS            http://wa8lmf.net/aprs
Symbols Set for UI-View,
UIpoint and APRSplus:

More information about the aprssig mailing list