PCM Advantages

Extremely accurate and undisturbed servo movement, even if the model is a long way out.Holding of the servo position during short glitches (Hold). Moving the servo's to a predefined position in case of a longer disturbance or even complete failure of the transmitter (Fail-Safe). Fast transmission if SPCM20 or PCM 1024, similar to PPM. Servo's are not damaged by pulses that are too long/short, which could happen with PPM.

PCM Disadvantages

PCM-receivers are more expensive compared to PPM. Because they are usually combined with a very good double conversion unit, they have the same size and weight as high-end double conversion PPM receivers. Sensivity to adjacent channels is usually worse than comparable PPM receivers. Care has to be taken when flying over a transmitter from an adjacent channel. Because of the different protocols, only receivers from the same brand or even type of the transmitter can be used. Innovative, flexible companies, offering automatic channel selection (SCAN-PLL), cannot use the protocol. PCM development thus runs a bit behind. Checking the transmission quality is very difficult, because the hold-mode irons out small glitches. The lack of early warning signs often causes trouble. Control problems that build up gradually ,e.g. of a technical nature, get noticed only when the connection fails completely, usually leading to a crash.