I needed to control /read my new ICOM 756PRO from WriteLog, and have been
able to get the above cable working between the standard serial port of my
computer and the input jack on the radio by only adding a Radio Shack
274-368 (1/8 inch stereo plug to 1/8 inch mono jack - $1.99).
With the RS adapter plug, the cable functions as if it were the CT-17,
except that it only has one radio connector instead of the CT-17's 4.
Details: The ADMS-1D is a cheapie package (I paid $30 new 2 years ago) from
Yaesu which contains software for programming some of the Yaesu radios
(including my VX-1R) along with a cable to connect from the computer to the
radio. The main cable includes an extension/adapter cable to allow the
package to work with Yaesu radios having 4-conductor mini earphone/data
sockets as well as 3 conductor ones. In addition, the cable includes a
bidirectional level translator inside the DB-9 which converts to/from TTL
levels.
Before trying with the radio, I plugged the cable into the serial port and
read the cable's signal levels with a VOM to verify that the signal was on
the center ring of the 3-pin plug and the common was on the base, and
verified that the tip was not connected to anything. Opening up the db-9
verifies that only two wires are used.
The Radio Shack adapter plug is intended to convert stereo phones to mono
by paralleling the ring and tip signals from the jack and connecting them
to the tip of the mono plug. Just what I needed to "move" the signal to the
tip of the adapter, where it plugs into the 756PRO.
It works, and there is no mod or change to the cable - I can still use it
when needed with the VX-1R radio just by unplugging the cable from the RS
adapter plug and inserting it into the 4-conductor extension/adapter cable.
Been going several days now with the 756PRO - no problems.
Jerry W4UK
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