Hello Yoshiro -
I'm sorry you haven't been able to reach me via email. It's most likely a result of all the email "spoofing" of this past summer.
If you have the same email address you have used in the past, I will contact my ISP to see if they will allow your mail to get through.
PCM (Pulse Code Modulation), basically, is how the transmitter talks to the receiver. The signal from the receiver to the servos is still the same as all other systems - PWM (Pulse Width Modulation).
There are an awful lot of people using APC-3 with PCM radios so I guess it's safe to say that it works! And don't forget that if your boat has bow planes you can bypass the receiver entirely by using APC-3 (as well as APC-4) in stand alone mode. Just feed 5 volts to it.
The U.S. of A - Land of the Free BECAUSE of the Brave