MM>         A fellow ham has a simplex autopatch up, using the * key to
 MM> open it and the # key to close it, as is common here. Problem is, he
 MM> tuned it (it's an old simpatch) using his HTX-202 as the test for
 MM> proper decoding. My standard ICOM 2-AT won't access it, neither will
 MM> his other handheld radio in later tests.
RW>  Does that old simpatch use 556's as a tone decoder?  If so,
RW> you can tune them seperately by pressing two buttons...
        You're right, it *did* use the 556's. He's come up with a plan now to 
use a DTMF decoder chip instead that is "fail safe" (dangerous word) at 
decoding the tones and has got it successfully decoding on the test bench. 
Now it remains to disable the decoder in the device, and insert the new.
        Thanks to all for help and info on this.
Mark  KC7RUB  
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