[chirp_users] chirp issue with IC92AD

Richard E Ravich richard at ravich.us
Sat Sep 20 16:00:23 PDT 2014

Interesting problem -- I had one of those older USB to serial cables 
that had the old Prolific chip in it and it was blocked by the newest 
drivers that are in Microsoft, so I purchased a Plugable USB to serial 
converter which is supposed to have the later version of the Prolific 
chip in it.

I tried it using the RS92 software from Icom and it works just fine, but 
using it with chirp, it appears not to be communicating with the radio 
because if I disconnect the radio, I get the same information back as I 
do if the radio is connected -- all invalid. I don't suspect that the 
problem is in the cable, but it could be the issue and maybe I need to 
go out and buy a third cable with the acceptable chip in it to get chirp 
to work.

Does anyone know what the voltage of the signals are coming from an 
IC92AD?  Are they "true" RS232 signals (ie +12 to -12 volts) or are they 
TTL voltages 0 to +5 volts?  Is there a way to tell the Prolific chip 
that these are TTL voltages and not RS-232 voltages? Maybe that would 
help some people.

Richard Ravich

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