The CM11A is a bi-directional X10 controller that connects to a serial
port and transmits commands via AC power line to X10 devices. This
module translates human-readable commands (eg. 'A2', 'AJ') into the
Interface Communication Protocol accepted by the CM11A. Both the send
(control output) and receive (monitor external events and status)
operations are supported by the module. The module also handles
checksums and retries failed transmissions.