[aprssig] Kenwood "TC" command

Stephen H. Smith wa8lmf2 at aol.com
Sun Jun 19 22:23:50 EDT 2011

On 6/18/2011 1:20 PM, Lee Bengston wrote:
> On Wed, Jun 15, 2011 at 6:16 PM, Stephen H. Smith<wa8lmf2 at aol.com>  wrote:
>> The D700 and TH-D7 are notorious for a too-small buffer that overflows in
>> KISS mode, since the entire raw packet including headers, etc lands in the
>> buffer before being passed to the external terminal, (rather than just the
>> packet payload as it does in the standard command-line mode).    The problem
>> is aggravated by high traffic rates on the RF channel, especially if a lot
>> of longish packets such as raw NMEA posits or weather station data are
>> present.
> Wouldn't that tend to affect either packet mode or KISS mode when
> using APRS software, or does KISS mode need more RAM and ROM?
> Lee - K5DAT

KISS requires more RAM to be assigned to the I/O buffer.  In normal PACKET 
mode, only the packet payload and the path is passed to the external computer.  
In KISS mode, the entire raw received packet is passed to the computer, 
including a lot of packet overhead that you never see in the normal command 
line mode.

The length is right on the ragged edge of what causes the buffer to overflow.  
You may get a hundred packets through in KISS mode just fine, and then it 
crashes when an exceptionally long weather station string or a raw NMEA posit 
comes through. Or someone messaging types off the end of the line and wraps 
into a second packet for the rest of his message.



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

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