The function write-serial-port-char
writes the character char to the serial port associated with serial-port, and returns char.
A timeout will occur if the character cannot be written before the write timeout (as specified by values given when the serial port was opened by open-serial-port).
When a timeout occurs, if timeout-error-p is non-nil, then an error of type serial-port-timeout
is signaled, otherwise nil
is returned. The default value of timeout-error-p is t
.
LispWorks User Guide and Reference Manual - 13 Feb 2015