[RTTY] Keying circuit interface

[rloranger@sympatico.ca (Robert P. Loranger)]

I built the interface described in the MMTY Help file. It uses one
transistor, 2 diodes and 2 resistors. I used a 2N3904 transistor.
Both FSK and Xmit keying built on perf board squeezed into the shell of
a DB9 connector. Tight fit indeed.

Why did I do that? Well I built it the day before BARTG and I simply
could not find a suitable enclosure in the junk box. Pity.

FYI: the rig here is the IC-751A. Great rig for RTTY.

Cheers,
        Bob VE2AXO