[RTTY] FSK Keying of TS-590SG

[David G3YYD]

Tim

Use a switching transistor as per N1MM wiki on interfaces see http://n1mm.hamdocs.com/tiki-index.php?page=Serial+Parallel+and+Sound+Card+Interfacing&highlight=interface+cw#Interfacing_for_PTT_and_CW_Keying 

Opto-Isolators are not needed. 

Even better would be to use AFSK as that will have narrower transmission width than rig based FSK. It will also be jitter free unlike MMTTY FSK making copy at the far end better. If you use MMTTY AFSK then configure it for the TX filter on with tap set at 51, the default setting for this is not very good.

73 David G3YYD

-----Original Message-----
From: RTTY [mailto:rtty-bounces at contesting.com] On Behalf Of groupsrichart at gmail.com
Sent: 23 February 2018 19:49
To: KenwoodTS-590 at yahoogroups.com; rtty at contesting.com; TS-590 at groups.io; TS-590S at yahoogroups.com
Subject: [RTTY] FSK Keying of TS-590SG

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

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