[aprssig] Polling a Kenwood APRS Rig ... Yet more

[Brian B. Riley]

Curt (WE7U) and I have had some back channel discussions winding up with me
braving the frigid weather on NWVT today and getting to my D700 in the
truck with my D7 ... here's the scoop ...

I took my D7 and set the D700 to P.MON (monitor TNC) ...

On either Kenwood rig, if you enter a message with a '?' as the FIRST
CHARACTER of the message text, the Kenwoods treat it as a directed query and
gets no sequence number, is not ACKed and the Kenwood responds with a Posit.
For instance:

  "?APRS?"

However, if you insert some text such that the first char is not a '?',
like:

 " m ?APRS?"

It is treated as a message and gets a sequence and is ACKed and the Kenwood
does not respond with a Posit.