!!! every byte is "echoed" by the µC !!!

Set Value via Digitinput (MSB first)
PC  Address ("CR" not allowed)
PC  channel no. (ranging from 0 to 8, number as ascii code)
PC  Digit 4  (ranging from 0 to 9, number as ascii code)
...
PC  Digit 1 (ranging from 0 to 9, number as ascii code)
PC  "CR"

Example: "A04012"
device address A; channel 0; value 4,012

Please note:
The command end sign is not allowed to appear at any other position.
If channel no. is out of range the command is ignored.
Further characters following digit 1 will be ignored. Commands with
more than 128 bytes will lead to an overflow. The length of command
lines for non µC control devices is not limited.