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-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.