Few questions about the W5XD keyer circuit. I have the
chip and am building my own keyer. The circuit
published on the Writelog info page is for the older
version of the keyer, and I understand it does not
include all the features of the new one.
1. Does the L/R switch force left or right when pin 21
of the MC68HC705P is grounded? Is the normal (software
switching) condition of that switch grounded or open?
2. I assume that the sidetone volume just changes the
drive level to the 2N2222? Or is there some additional
circuitry? It would appear from the published circuit
that sidetone always/only goes to the left headphone.
Is that correct?
3. Do the REC and PBACK pins on the IC do anything?
The reason I am building my own circuit, apart from
being cheap, is that I want some other features not
available from the standard product.
Many thanks for any information.
73 Roger
VE3ZI
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