[ICOM] civ Noise on polling rig

[Marios Nicolaou]

Dear All
I used a 756 pro III for the first time during the contest yesterday and I
noticed that when the radio is being polled by a homemade CIV interface
(FTDI 232 based)  there is a very short burst of noise in the receiver.  If
I turn the CIV transceive option ON in the software there is no noise  when
the frequency doesnt change but when I turn the VFO this associated with a
burst of noise until I stop turning.

Is this "normal" or could this be a weakness of my interface? Would adding
optoisolators after the ttl conversion (eg max232) take this noise away?

-- 
Marios
5B4WN