[CoARES-D10] UI-View HSP switch problem

[Dar743@aol.com]

I built this switch as shown in the UI-view help file.  I used 2N4401 
transistors, 1N914  diodes, and 1/4 watt resistors.  I have a KPC 3+ and a Magellan 
310 connected to the switch through a "Y" cable, and have the TNC  in "KISS" 
mode.  

When I connect ONLY the TNC to the HSP switch, I get normal APRS operation   
as expected.  When I connect ONLY the GPS to the HSP switch, ui-view polls the 
GPS at the expected intervals and  good GPS data is received and acted on by 
the program .

However ( and a frustrating HOWEVER), when I connect both the TNC and the GPS 
at the same time, I get normal APRS data  until the program polls the GPS. At 
that time, I get COMMS ERROR  and no GPS data.  The program then goes back to 
normal APRS operation until the GPS is polled again.

I would tell myself that the problem is the TNC isn't shutting off soon 
enough to accomodate the GPS, but I installed the R4 resistor and D3 diode that 
should  send the TNC data to the RTS line in such an event ( apparently unlikely 
in KISS mode).

I would appreciate any thoughts on the subject.  Some of you may remember the 
  old protest song lamenting the man "who would ride forever neath the 
streets of Boston", stuck on the MTA (subway) for lack of a nickle  to pay for the 
transfer.

  Until I find a solution to this problem (obsession), I am stuck forever in 
the basement.

73's

David
KA1BXM

                                                        


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