[Elecraft] K3 RTTY setup with MMTTY

[Richard Ferch]

Julius,

If you want to use FSK without giving up radio control you will need two
serial ports - one for radio control and one for FSK keying. You cannot do
FSK on the same port as radio control (unless you are using the KY; software
command, which the vast majority of software, including MMTTY, does not
support). If the port you use for FSK is a USB-to-serial adapter rather than
a true serial port, you will need to use the EXTFSK plugin for FSK.

In MMTTY you must configure a serial port for PTT (different from the radio
control port) in order to use FSK. However, you don't actually have to use
this port for PTT; you can configure it, enable it for FSK, and then just
not connect aany PTT line to DTR or RTS. MMTTY gives you two other
alternatives: you can do PTT either by software control or by keying DTR and
RTS on the radio control port.

If you use MMTTY's PTT port for FSK and/or PTT, both FSK and PTT will
require keying transistors, because these inputs on the K3's ACC connector
are TTL-level, not RS232 (FSK from TxD via a keying transistor to pin 5, PTT
from either DTR or RTS via a keying transistor to pin 4). If you choose to
do PTT using the radio control port (either DTR or RTS), you will not need a
keying transistor for this line, because this is an RS232-level input on the
K3.

For the radio command protocol, just choose Kenwood.

The K3's AFSK A mode is operationally equivalent to FSK D, but does not
require an FSK keying circuit; instead, you need an audio cable between the
sound card's line out and the radio's LINE IN jack.

73,
Rich VE3KI