[aprssig] How to send packet through a KISS modem

[Jason Rausch]

Rob,

I ran into a few things that kept me from transmitting as well.  One was the port byte indicator.  I would have to go back and look at the spec to tell you where it goes, but it is one of the first bytes after the first FEND.  Also, when you saw "raw packet" wrapped in FENDs, does that mean you are not "encoding" it in the correct format?  Just a raw ASCII packet?  If you are decoding, then you understand the format that the packet is given to you and you must send a packet to the TNC in this same format.

Just for reference, check out the analyzer program I wrote for learning how a KISS packet works (its the last program on the page):

http://www.ke4nyv.com/software.htm

Just paste in a raw KISS packet and it will break down every element for you.  It is quick and dirty, but it helped me a lot.

Jason KE4NYV
RPC Electronics
www.rpc-electronics.com


--- On Mon, 8/3/09, Dave Haynes <dave at ep90.com> wrote:

> From: Dave Haynes <dave at ep90.com>
> Subject: Re: [aprssig] How to send packet through a KISS modem
> To: "TAPR APRS Mailing List" <aprssig at tapr.org>
> Date: Monday, August 3, 2009, 4:51 AM
> Are you sending the type indicator
> byte before your packet? After your opening $C0, the first
> byte indicates the content of the message to the TNC. For a
> data packet, the indicator byte will usually be $00.
> 
> All detailed in "The KISS TNC: A simple Host-to-TNC
> communications protocol" by Mike Chepponis K3MC and Phil
> Karn, KA9Q
> 
> Dave
> G1TVL
> 
> rfinesmith at aol.com
> wrote:
> > Does anyone in the group have experience programming
> to a KISS modem to transmit?  I have no problem
> receiving and decoding APRS packets from a TNC in KISS mode
> (using a my Kantronics KPC3+), but I can't figure out how to
> get the TNC to send packets while in KISS mode.  I am
> wrapping my raw AX25 packets in \xC0 prior to writing to the
> modem, but that doesn't work.  Also, I have tried to
> manually send text while in kiss mode, using HyperTerminal,
> also wrapping the text in \xC0 (i.e.,
> <ALT>-0192).  No luck.
> > 
> > Thanks,
> > Robin, AA3NJ
> 
> 
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