----- Original Message -----
From: "Adi Linden" <[EMAIL PROTECTED]>
> > It is CTCSS encode/decode...didn't you see my other post....that's what
> > the MN6520 chip is!
>
> Great! Thank you. Sorry, I didn't read your post until after I replied.
> Any idea where I can find information on this chip? I've goggled for this
> extensively before posting the question here. No useful results searching
> the web.
If it is the same chip used in the Kenwood 601/701/801 radios, it is a PROM
chip that has a built-in decoding system, used with a programmer, to burn the
PROM with info. A drop-in replacement for the chip is a 74ls188 PROM.
Simply drop yours into a programmer, read it, analyze what you need to tweak,
then burn it into a 188 PROM chip. I had a 601, a ham Elmer and I decoded
what was on the chip, what it did, and decided that a PROM would be much
easier to handle than getting the Kenwood programming tool. (In the 601,
two chips controlled the xmit and rec frequencies, and a 3rd on a separate
board did the CTCSS.)
I thought I still had the old PROMs here, but I still have the first test-set
of where these hard-wired pins will put a -601 on F1 at 52.525. Probably
won't help you out, but it's in the right direction. :-)
_Ray_ KB�STN
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