[drats_users] Arduino and D-RATS

[Dan Smith]

> I've looked at the source files and I could get a little info from
> them since I'm not experienced with programming. The structure of the
> packets is clear now; I'm just not sure how the variables are
> calculated like the magic number or the checksum or the lengths.

The magic number is fixed for non-compressed packets: 0xDD. The length
is the length of the payload (i.e. everything after the last character
of the destination callsign up until the [ of the [EOB].

> A sample packet that I got over a terminal was
> [SOB]"=@=@=@=@TIMOTHY9CQCQCQ~~Test message.[EOB] Would the =@ be the
> magic numbers or is it just that the encoding in the terminal is off
> and is interpreting the values as "=@"s?

Yeah, don't trust that as being right, the terminal can do many weird
things because it can be interpreting any non-ASCII characters as
control characters. You need to capture the stream in binary and look
at it in a hex dump in order to really know what's going on. You could
also instrument some of the D-RATS code to generate packets and then
hexdump them so you can see what the packet is going in and coming
out.

-- 
Dan Smith
www.danplanet.com
KK7DS
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 490 bytes
Desc: not available
Url : http://intrepid.danplanet.com/pipermail/drats_users/attachments/20130113/2873a40e/attachment.bin