The invention provides a solution/device for controlling external
parameters by use of the same data cable and specific software to
transfer/receive messages and monitor/control external parameters in a
system. Additionally, the invention is compatible with ATA/ATAPI by using
the ATA protocol or side-band protocol to make a main system communicate
with other device(s) through an ATA/ATAPI device's data cable. Also, the
invention uses the system's data cables and a non-standard controlling
sequence to transfer and receive messages by the same cable to connect
with the external devices for monitoring/controlling external parameters.
Hence, the number of data wires needed is reduced. Also, the invention can
decrease the manufacture costs and get a better heating dissipation.