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  ICOM IC-900/901 Series Band Unit Identification Select Explained
by Chris Baldwin KF6AJM
HTML'd for repeater-builder by Mike Morris WA6ILQ
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I recently purchased a set of ICOM IC-900/901 series band modules, along with an FC-900 interface to attach to one of my ACC repeater controllers. In the package, I received three radios, along with three interface boards that were separate from the radios.

Some of the radios were originally used with a Link Communications IC-900 series interface kit. This kit includes replacement front PC boards for each band module that are specific to the Link Communications way of interfacing the ICOM IC-900 series radios to Link Communications RLC-series repeater controllers.

Luckily, the original owner was thinking and kept the original ICOM interface boards (and included them with the radios) so I could convert the radios back to the ICOM factory-original state that the FC-900 and ACC controllers require them to be in for remote control.

Little did I realize, though, that these interface boards have to be set to indicate what type of radio they are attached to or you’ll run into problems.

After connecting everything together and testing it on the FC-900 and ACC controller, I found that my 440 radio was responding to commands issued for 2 meters, my 10 meter radio thought it was a 6 meter radio, and 2 meters thought it was 440.

After scratching my head for a bit, I pulled the boards I had put back on the radios and realized that on the back side of the board are seven solder jumper pads labeled 0, 1, 2, 3, 4, 5, and 6.

Having another FC-900 interface and another 440 module, I disassembled its radio and noticed that solder jumper pad "5" was jumpered.

Knowing that the ICOM 900 series was offered with 10m, 6m, 2m, 220, 440 and 1.2GHz, and seeing that the working 440 band module was set to "5", I figured out by trial and error that the solder pads indicate the band module identification, and they are as follows:

So I matched the two boards that I had to the two correct radios, and moved the solder pad on the 10 Meter module from the "2" position to the "1" position, reconnected everything, and lo and behold all of my modules are now addressed correctly, and everything is working as it should.

This information was not documented in any ACC documentation I have, and the IC-900/901 documentation is scarce at best, so hopefully this document will help someone in the same situation.

Encountering these radios in a mismatched configuration is probably pretty rare, and the only reason I encountered it was again, because I was converting the radios from Link Communications interface boards back to ICOM stock interface boards.

Acknowledgements and Credits:

ACC is Advanced Computer Controls, now part of Link Communications, http://www.link-comm.com.

Contact:

Chris Baldwin KF6AJM can be reached at: support [ at ] advancedcomputercontrols [ dot ] com


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This page originally posted on 29-Jul-2009


Article text © Copyright 2009 by Chris Baldwin KF6AJM. All Rights Reserved, including that of paper and web publication elsewhere.
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