CIGAL Reference Manual, Chapter 2 (Commands): COMWRITE
usage: comwrite buf [chan]
COMWRITE writes the byte data into a BUF variable and sends it to the communication port specified by CHAN. If CHAN is omitted, the first output port is used by default. BUF can be either a character string variable or a byte array variable (see DECLARE(2)). Before writing to a serial communication port it should be configured by setting the COM1(4) (or COM2(4)) parameters. To read from a communication port use COMREAD (see COMREAD(3)).