[TRLog] PTT output and 1000MP
Wed, 8 Aug 2001 11:24:13 -0800
>> I am using the standard TR LPT port keying and PTT interfaces with a
>> 1000MP Mark V (1K resistor to base of open-collector 2N2222, emitter to
>> strobe line, open collector to plus of keying or PTT jacks). Previously
>> these interfaces worked fine with my TS-930. Either one will key the Mark
>> V's CW, but neither one will key the PTT line at the jack on the back (in
>> other words, the interfaces appear to be functioning as designed).
>> Anyone else had this problem? How did you cure it?
>Try putting the emitter to ground. The strobe pin will limit how
>much current can be sunk - and also result in a slightly higher
>"low" voltage. This could be the difference.
This will probably fix his problem, often it's PC LPT port dependent
and another PC will work fine. The strobe is a good idea however
as the program doesn't come up keying the radio PTT. I solved
this by having the 2n2222 key a reed relay for both CW and PTT.
Also adds isolation between the radio and PC port.
73 Rich KL7RA
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