[RTTY] Yaesu FT-920 setup - HELP!!

[Ian White, G3SEK]

John Fleming wrote:
>
>> To repeat a previous message, I've had no problems with two - no, make
>> that three - different types of regular non-Darlington opto-isolators
>> keying the PTT, CW and FSK inputs of an MP. It would be very surprising
>> if the 920 required different levels, since all that generation of Yaesu
>> HF rigs are re-using a lot of the same circuit technology.
>
>Ian, what "regular" optos did you use?  I've heard of some successes, but
>not with the 4N-series, e.g. the 4N25.
>
Devices that I either know personally, or know of, that have 
successfully keyed various inputs of the MP from a PC's RS-232 ports 
include:

CW :
4N33 (Darlington, CTR 500% @ 10mA) with 560R input resistor
4N36 (transistor, CTR 100% @ 10mA) with 470R input resistor
MCT5211 (transistor, CTR 110% @ 1mA) with 1k input resistor
FSK :
SFH618-A3 (transistor, CTR 100% @ 1mA) with 2.2k input resistor
TIL117 (no details handy) with 2.2k input resistor

CTR = current transfer ratio, which is the opto-isolator's version of 
"gain".

The CW keying circuits are in G4AXX's and my own PC-MP interfaces, at:
http://www.granta.digital-crocus.com/equipment.php3

The opto FSK interfaces came straight out of the WriteLog Help files. 
They are stuffed inside DB9 plugs... and please don't *ever* ask me to 
open them up again...

G'night all.

-- 
73 from Ian G3SEK