[aprssig] APRS Telemetry Question
Lynn W. Deffenbaugh (Mr)
ldeffenb at homeside.to
Sat Oct 13 14:53:39 CDT 2012
On 10/13/2012 3:01 PM, Steve Noskowicz wrote:
> As I said, APRS101 that I have (aug 2000) does not mention the #. It only shows it in the example. Therefore, the Telemetry data payload packets MUST begin with "T#nn" (and perhaps "T#n") not just "T" as 101 states.
> With the data type definition being the "T" it seems to me that the "#" is redundant and a wasted byte, no?
I don't question the protocol specification, I just attempt to
understand and implement it.
If you look closely at the Telemetry Report Format on page 68 of
aprs101.pdf, you'll see that the Sequence No. is specified as #xxx, for
a total of 5 characters. Yes, the # is part of the protocol
specification and not just in the examples. Every single character in
those format specifications is part of the specification, especially
those highlighted in yellow.
Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32
PS. I didn't know a single thing about APRS when I started over three
years ago. I spent many a night reading and re-reading aprs101.pdf and
examining sample packets from aprs.fi's raw displays. It takes time to
find and understand some of the nuances, but most of the basics are in
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