[ICOM] ICOM interface question

[Frank A. Ellis]

Chuck,

The EX-309 was designed to use a parallel interface.
It will not work with the CT-17, which is serial. At
the time the EX-309 was designed, most rig interfacing
was experimental and performed by hardy hams who wrote
their own code to allow access to the EX-309 via a
parallel computer interface. One example of this that
comes to mind was some BASIC source code that was
published in one of the ham magazines (maybe Ham
Radio?) in 1985 or so, showing how to write and use a
BASIC program to allow (from what I remember) a
Commodore machine's parallel port to control the radio
via the EX-309.

In any case, the original EX-309 interface was almost
immediately abandoned by ICOM in favor of the later
UX-14 and it's serial interface, which I believe was
offered due to the increasing popularity of the
then-new IBM PC and it's available serial port(s).

The "guts" of the EX-309 and UX-14 are nearly
identical, except for the computer-side interface. If
someone was very motivated, they could probably figure
out how to modify the unit for a serial I/O on the
computer side.

The CT-10 Communications Terminal was ICOM's intended
interface point to the EX-309. The CT-10 was primarily
an RTTY interface (with selectable Mark/Space filters)
that had a computer control interface added, probably
as an afterthought. 

For computer interfacing, The CT-10 provided a
level-shift function for the EX-309 similar to the way
that the serial CT-17 operates. The CT-10 is
exceedingly rare, probably never marketed here in the
U.S. and likely only ever existed as a few trade-show
hardware demo units, based on information I have
collected over the years.

Sadly, a lot of owners of the IC-751, older 751A's,
and R-71A's look to purchase the EX-309 because it's
what their owner's manual says is needed. The older
manuals were written before the UX-14 was introduced
and the rig owner is generally stuck with it after the
purchase.

Will the EX-309 work? Yes, with some effort. Can it be
modified to interface to serial? Probably could be. If
you choose to go the second route, it would be very
interesting and I am sure a lot of hams would love it
if that information would be shared.

I can highly recommend the PIEXX UX-14PX clone, it has
all the features of the original plus some things the
original did not have, like band stacking registers,
9600 baud, and a PTT interface.

73, and I hope this information is helpful to you.

Frank, W3UHF






--- KI9A at aol.com wrote:

> Guys-
>  
> I bought a new-old-stock ICOM EX-309 computer
> interface board, that allows  
> the ICOM 740-745-751 series rigs to be computer
> controlled. But, after getting  
> the thing on EBAY (not here yet), it seems it works
> with an old ICOM CT-10. I 
> am  wondering if I screwed up, thinking it will work
> with the CT-17? Anybody 
> know  anything about these? If it is designed to
> work with the CT-10, can I 
> make it  work with the CT-17, or, am I better off
> putting it back for sale?
>  
> 73-Chuck KI9A
> ----
> Your Moderator: Dick Flanagan K7VC,
> icom-owner at mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.316 MHz
> Icom FAQ: http://www.qsl.net/icom/
> 



 
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