[WriteLog] Re: [RTTY] Re CW Intreface

WA9ALS - John wa9als@starband.net
Sat, 13 Apr 2002 23:11:15 -0500


> anymore ideas

Did you build the optoisolator interface that's shown for the com port, or
the transistor one shown for the LPT port?

I'll bet you built the optoisolator one with the 4n33?  If so, I'll bet if
you use the other one with the plain ole transistor, it'll work!  Depending
on the rig, sometimes the optos don't pull low enough to key PTT, so I would
presume CW keying too.

Just send your serial port DTR through a 1K resistor to the base of a 2n2222
or 2n3904.  Ground the emitter, and send the collector to your key input.
Ground of serial port to emitter and on to key input ground.

This is based on the KISS principle.  Yeah, the grounds aren't isolated,
blah, blah, blah.  Many of us use this simple switch, mine for 3 yrs or so,
without problems.