[RTTY] FSK Keying of TS-590SG

[groupsrichart at gmail.com]

I would like to hear from anyone who is successfully keying the FSK and 
PTT lines via the ACC2 connector on the rear panel of the TS-590SG. What 
serial adapter and what hardware interface are you using to do so?

I have tried two different interfaces using optoisolators to attempt FSK 
and PTT keying from a serial card to the rear panel ACC2 connector. Both 
attempts have failed. I am using MMTTY software for keying and I do get 
the requisite signal change on TXD pin 3 (FSK) and RTS pin 7 (PTT) 
lines. I have also verified proper setup of the '590 by manually 
grounding the inputs PKS pin 9 (PTT) and RTTY pin 2 (FSK) on the ACC2 
connector.

However, I *think* the problem lies with the serial card not providing 
enough voltage/current for the optoisolators to completely turn on and 
provide a hard ground to the ACC2 inputs. I have tried two different 
serial cards and one swings from -4.9 to +5.0 VDC on the data lines and 
the other card swings from -3.8 to +3.9 VDC. The cards I am using are a 
two port generic PCI Express SI-PEX15037 and a four port Perle Fast 4 
PCI card. Does anyone know of a serial card that has a full -12 to +12 
VDC swing?

One of the hardware interfaces has 4N25 optoisolators and the other uses 
Fairchild FOD852 optoisolators. There are 1K series resistors in the 
input line to the optoisolators and I have tried various values (100, 
220 & 470Ω) with limited success but nothing consistent.

While my objective was to keep the rig isolated from the computer, I am 
thinking about building an interface that uses NPN transistors for 
keying. Is anyone using NPN transistors to key their '590? Are you tying 
the ground from pin 5 of the RS-232 port to the pin 4, 8 or 12 ground of 
the ACC2?

Any input is appreciated...I have been off RTTY since purchasing this 
rig in November and I want to get back on the bands.

Thanks,

Tim WS4V