[RTTY] UPDATE Re: FSK Keying of TS-590SG

[groupsrichart at gmail.com]

Just to give everyone who has commented a little update:

1. I located another serial card and installed it in my computer. It 
gives me a full -/+12VDC swing on the data lines.
2. The optoisolators in my interface are not pulling the PTT and FSK 
inputs of the rig low enough to work. When the optoisolator is turned 
on, I am still seeing +0.54VDC on the ACC2 inputs to the rig.
3. I tried different values of current limiting resistors from 100Ω to 
1.5KΩ on the inputs to the optoisolators with no change.
4. I checked my junk box for some NPN transistors and found none (I 
could have sworn I had some 2N2222s), so I have a few on order for the 
coming week. I plan to build the simple resistor/transistor interface 
that many have suggested.
5. After I get FSK working, I do plan to also try AFSK. There seems to 
be a spirited debate among many as to which is best. I have no doubt 
that either method properly used can give good results so I want to find 
out operationally which method I prefer.

My thanks to everyone who has taken the time to respond with your 
comments and suggestions. I found them all very helpful.

73,
Tim WS4V

On 2/23/2018 2:49 PM, groupsrichart at gmail.com wrote:
>
> 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
>