Icom IC-746 Faq page 60

KD6UU posted detailed schematics and instructions on eham.net:
http://www.eham.net/articles/1588
and then wrote an excellent updated follow-up article at:
http://www.qsl.net/kd6uu/icomci.html
Designs have been published in both QST and CQ magazines.
"Everything You Always Wanted to Know About Hardware For Computer-Controlling
Modern Radios"
Blackburn, Wallace, AA8DX
February, 1993, QST, p.37
"A Low-Cost PC Interface for ICOM Radios"
Thompson, Nigel, KG7SG
July, 1992, QST, p.37
Far Circuits has some of the required PC boards at:
http://www.farcircuits.net/
The actual design of the interface circuit is subject to debate (as the above link will make
clear). Several alternative designs (along with a wealth of related information) are available
from DF4OR's WWW site at:
http://www.plicht.de/ekki/civ/
A few other sources for CT-17 circuit information are:
http://www.seed-solutions.com/gregordy/Amateur Radio/Experimentation/CIVInterface.htm
http://www.oz1eqc.dk/Downloads.htm
http://www.g3vgr.co.uk/civ.htm
The OZ1EQC version of the circuit allows the use of the same COM port for both CT-17
control and RTS style keyer control. The software configuration implications are left as a
puzzle for the reader.
When building the G3VGR version, AD6ZU makes the following observations:
I found that the G3VGR interface to be quite easy to build inside the DB-9 shell. The
parts are cheap and it's quite tolerant to using components not listed on the schematics.
I used 2N3904's instead of 2N2222's because they were what I had. I also used 5.1K
resistors instead of 4.7K and had no problems with the interface. I've built about a half
dozen so far and the suggestions I have for this interface are:
Start with the shortest connections (the shorting of the pins).
Imagine working from the connector toward the back of the shell. This makes for a
much neater layout than randomly building the circuit "ugly style". You can practice by
building your first interface that way since the parts are so cheap it's easy to build
another one.
IC-746 FAQ
Page 60 of 113
2003-02-08