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  ACC Introductory Information
Compiled by Mike Morris WA6ILQ

The ACC file archive is located on the Link Communications server at Look for the ACC page, and then go to the "File Archives" page. There you will find a download directory which contains a zip file for each ACC product.
Each zip file is a comprehensive upgrade kit to the last software revision for that product.

Apparently Link Communications no longer deals with ACC equipment; RLC Communications has taken control of that product. You can find files etc on their site by clicking here. And RLC was purchased by Audio Test Solutions, Inc. Are you confused yet?

Last we heard, Link/RLC/ATSI also had the following:

Shipping on any of the above is additional. Prices listed are are as of the time of this writing (2001) and at that time were approximate. No guarantees as to prices or availability now.

The RC-850 started production in the 1982/1983 era, which makes the oldest units out there way over 25 years old. Have you backed up your memory chips lately???
If you don't have backups of the EPROMs in your ACCs, and of the EEPROM in those that have them you need to do it ASAP - they do start to drop bits eventually. The EEPROM contains all of your IDs, Timers, Autodial numbers, etc. I am willing to bet that most repeater tech folks DO NOT have a complete and current list of every Courtesy Beep, ID string, Timer value and Autodial locations...
If you don't have a Computer Interface Board on your RC-850, pull the EPROMs and the EEPROM chip and read each one individually using a PROM burner and a desktop or laptop. If you do have a Computer Interface Board just log in and download an e2prom.hex file (that will get the EEPROM contents, you will have to pop the lid and get the EPROM images on your own). Paul Kindell WB8ZVL, "The ACC Repair Guy can create a replacement EEPROM chip from the e2prom.hex file.

Aged Capacitors:
To continue the list of problems with old equipment, electrolytics dry out and cause problems... the capacitor values go down, the audio gets raspy, the levels change, or get intermittent. The lower values of the caps used as bypass or filtering can really affect things.

One problem that has bit several people badly is that the audio processing opamps in all the ACCs run on bipolar voltages, and the negative supply is an interesting design: an LM386 speaker driver IC is AC coupled to a negative rectifier, and as the filter caps dry out and the values go down the negative supply develops a bad ripple at a frequency of about 15 KHz. If the audio processing in your repeater transmitter exciter is inadequate your repeater can develop spurs every 15Khz up and down the band. So if your controller has never had the caps changed, and you have some strange problems consider shotgunning all the electrolytic filter, bypass and coupling caps. Oh - and tantalums make great filter and bypass caps but don't use them as coupling caps as they change value with the voltage across them. You will want to use metalized plastic film electrolytics as coupling capacitors as they have the lowest distortion.

Courtesy Tones / Beeps:
While not ACC-specific, there is separate tech info web page at this web site that is a collection of manufacturer default and user-created courtesy beeps   (trust me - the "Nextel Beep" is cute, but becomes very annoying after a while).

Firmware bugs and patches:
No firmware is perfect, and ACC certainly had a few bugs in theirs. ACC is no more, and Link/RLC/ATSI owns the remains, and provides NO support, and probably doesn't care. Undoubtedly there are repeater groups or even individuals that have reverse engineered / disassembled the firmware in the various ACC boxen (yes, that is an accepted plural of boxes) to fix bugs or to add features. If anyone would like to write up their patches, even anonymously, feel free to do so. Just contact article-ideas //at// repeater-builder //dot// com address, or if you really want to be anonymous, just drop a CD into the mail to Mike WA6ILQ at his snail mail address (which you can get from

System Interfacing:
ACC was the first really successful commercial controller, and the companies that followed them had the opportunity to resolve some of the ACC design "gotcha"s. One was that the ACC required active high signals on several of the incoming signals (like CTCSS decode). The later controllers offered inversion on each signal, either by software or hardware jumpers.

This page split from the main index page 16-Nov-2011.

This web page, this web site, the information presented in and on its pages and in these modifications and conversions is © Copyrighted 1995 and (date of last update) by Kevin Custer W3KKC and multiple originating authors. All Rights Reserved, including that of paper and web publication elsewhere.