[aprssig] TH-D7 & KISS MODE

Steve Gladden steve at michiganbroadband.com
Thu May 5 00:48:23 EDT 2022

>>>However, the first gen Kenwood APRS radios were notorious for buggy, unstable KISS operation.

Just thinking out loud and making conversation-

1. Why would Kenwood even bother to do that and not test to make sure it’s good,useful and reliable.
2. Why would it not be updated/fixed after being found to be bad, even if you had to send the radio to a service center to have it done.


From: aprssig <aprssig-bounces at lists.tapr.org> On Behalf Of Stephen H Smith via aprssig
Sent: Tuesday, May 3, 2022 4:04 PM
To: MJ Inabnit <ke6sls at arrl.net>; TAPR APRS Mailing List <aprssig at lists.tapr.org>
Subject: Re: [aprssig] TH-D7 & KISS MODE

On 5/3/2022 2:36 PM, MJ Inabnit wrote:

Bought a super cool old Kenwood TH-D7 from the 1990's.  It works! :)

Playing with data cable.  I can do APRS using the command mode, but my

efforts failed by putting it into KISS mode.  It would only transmit the

TXDELAY carrier and no data.

Anyone get this rig into KISS to use a computer aprs program?

The commands to enter KISS mode are similar to many other vintage TNCs.

from COMMAND mode prompt:



However, the first gen Kenwood APRS radios were notorious for buggy, unstable KISS operation.

The D7 and D700 were actually originally made for a proprietary Japanese system that preceded APRS called NaviTra ("Navigation Transceiver").  About 2/3ds of the way down this page on my website is some stuff on NaviTra:


When NaviTra flopped in the Japanese market, the radio designs were recycled, with new firmware, for the then newfangled APRS.

Both the NaviTra predecessor radios, and the D7 & D700, are based on a TNC-on-a-chip design designed by Tasco, also a Japanese company.  [Tasco is probably best known for their fast-scan<-->slow-scan  TV scan-converter chip used in the Kenwood VC-H1 handheld SSTV device & the Model 70 SSTV scan converter box in the 1980s.]  The Tasco TNC chip , which is also used in the TS-2000 TNC,  was crippled by having too little RAM.   It worked fine for short Mic-E compressed position packets, but longer text strings would randomly overrun the chip's buffers and lock up the TNC when operated in KISS mode.

Note also that when the TNC is in KISS mode,  the GPS pass-through feature that would automatically route the NMEA GPS input data out the main serial port,  (saving the need for two serial ports on the PC) DOESN'T WORK in KISS mode -- only in the classic COMMAND mode.

Stephen H. Smith    wa8lmf (at) aol.com
Skype:        WA8LMF
EchoLink:  Node #  14400  [Think bottom of the 2-meter band]
Home Page:          http://wa8lmf.net

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