The serial protocol of the communication link between the low-level control board and the on-board PC is documented in the manual "manuel_demo_robuCAB_indI". "Manual" in this wiki refers to it if not otherwise specified.
Here is some general guildlines:
The configuration of the RS232 port is
baud rate=115200 , databits=8, parity=No, stopbits=2.
All message fields should be appended by a CR char.
No Space characters
Value must be signed and sign "+" should not be omitted.
For the serial command list and descriptions, check out Section 8.2 - 8.16 in the manual.