[RTTY] Omni V & FSK Conclusion

[WA9ALS - John]

> Looked at the schematic several times, and kept seeing the same thing, but
> it just wouldn't "click". In the Omni V the Mark/Space goes thru a 4148
> silicon diode, a 10k resistor, and finally a NPN gp transistor all after
the
> back panel jack. Tentec specs call for no more than +/-  15 volts for
> Mark/Space. TXD line nominally shows no more than +/- 10 volts. A quick
call
> to Tentec (thanks Paul and Eric) my thinking was correct. No interfacing
is
> necessary for Mark/Space, the interface is already there inside the rig !!

In the manual for Brian Beezley's RITTY program, he mentions that you MIGHT
be able to just send the com port output to the FSK pin without a transistor
switch.  I've done that, through a 1K resistor, for the MARK-V FT-1000MP,
IC-706MKIIG, and the IC-756PROII.  I made a box with 2 PTT and FSK
interfaces - The PTT lines use the transistor switch, but the FSK lines just
go from the TxD pin, thru a 1K resistor, to the SHIFT pin of the appropriate
acc connector.  YMMV depending on the rig.  73 - John, WA9ALS