[Xastir] My D700 says "EH?" almost every time it gets a "MYCALL" from xastir! Anyone else?

[William Gery]

I have been seeing this behavior for quite sometime on my D700. 

Bill 

On Fri, 2006-09-15 at 11:10 -0600, Tom Russo wrote:
> I'm trying to diagnose and fix an extremely annoying behavior that I have 
> always seen when connecting my laptop running xastir to the D700 in my 
> vehicle.
> 
> I just made a commit to interface.c that fixed the problem I was seeing below,
> but I don't much like what the solution was.  This mail is intended to
> document the symptom and explain the fix.
> 
> Xastir sends "MYCALL xxxxx-xx" every time it is getting ready to transmit
> a posit, followed by "UNPROTO...", then followed by the actual posit data.
> Both "MYCALL" and "UNPROTO" are preceded by a control C (to get the TNC
> back into command mode).   (ASIDE: The control-C before UNPROTO seems like it
> might be unnecessary, since the first one should have gotten us into command
> mode, but that's beside the point).
> 
> But almost every single time the "MYCALL" string is sent, my d700 replies
> "EH?" instead of "MYCALL was xxxxx-xx".  This has been happening from the
> very first day I ever connected my laptop to my D700 about 2 years ago.  The 
> first time it happened the result was that the still-new TNC didn't know my 
> callsign and SSID, and the posit went out with "NOCALL" as my callsign.  I 
> fixed it then by manually connecting to the TNC with a terminal program and 
> typing "MYCALL KM5VY-8" --- that stored my call sign permanently in the 
> nonvolatile memory, and so ever since then these "EH?" instances have been 
> unimportant, since until yesterday I only ever connected a single laptop to 
> the thing with a single SSID.
> 
> It became significant again yesterday when I tried to connect a different
> laptop with a different SSID --- the MYCALL line that xastir sends is, 
> about 99 times out of a hundred, getting an "EH?" and the MYCALL value isn't 
> getting reset, with the result that my KM5VY-5 laptop's posits were going out
> with KM5VY-8's callsign/ssid in the packet.  Once in a while, though, it DOES 
> work.  It appears to be random when it does, but it is extremely rare.
> 
> Since seeing this problem, I've tried now and then to figure out how to make
> it go away.
> 
> I have toyed in vain with inter-character pacing values --- setting a very
> long character pacing has NO effect on this behavior.
> 
> A few weeks ago I even tried changing the interface.c code to pause for
> a second or more immediately after sending a control C to the TNC, on the
> assumption that it was possible that the d700 pauses to think a while after
> being told to go into command mode (there are other places where it is 
> necessary to insert stupid delays so the D700 can work), but this also had no 
> effect.  No amount of pause up to *5 seconds* after the first control C had 
> any impact.  Scratch one theory.
> 
> And today I finally just tried something obvious: I hacked interface.c and
> added a carriage return to the string sent to the TNC, right before the 
> MYCALL.  This has, in quite a bit of testing, completely eliminated the 
> "rejected MYCALL" instances.
> 
> Now the "EH?" is coming as a result of the leading carriage return instead.
> That's why I don't much like the fix: it merely pushes the error message
> from the TNC onto a meaningless, null command instead of the important MYCALL 
> command.
> 
> Clearly, the D700 (or at least *MY* D700) has some Issues with the first
> command given after being returned to command mode from CONVERSE mode with
> a control-C.  I have no idea what those Issues are. 
> 
> I committed my changes to interface.c, because it seems a completely benign
> thing to have an extra carriage return before the MYCALL for a regular TNC,
> and it seems to be a necessary work-around for the D700.
> 
> So here's what I'm actually asking:
> 
>   - Do any other d700 users see "EH?" in their View Incoming Data windows
>     right before "UNPROTO was ..." and a posit transmission by your station?
>   - Does anyone have a workaround that I should know about?
>   - Does anyone have a guess as to why such a huge fraction of these 
>     MYCALL commands would be failing on a D700?
>   - Anyone want to hazard a guess as to what might make it stop doing this?
> 
> This note also serves as warning to users of non-D700 TNCs to be on the lookout
> just in case the leading carriage return I added to the MYCALL command is 
> NOT as benign as I thought it should be.  Please let me know if you see any
> strange behaviors resulting from this extra character in the outgoing command
> stream.
> 
-- 
William Gery - KA2FNK
Regional Systems Manager
National Weather Service
Central Region Headquarters
7220 NW 101st Terrace
Kansas City, MO 64153-2371