A communications system is arranged for serially chaining multiple
portable pendant peripherals to a portable host device. The system
enables multiple low power input/output peripherals to communicate over a
bi-directional data line with a portable host device such as a PDA or
cellular phone. Fixed-length data packets are employed in a
store-and-forward approach between the host device and the pendant
peripherals. An upstream pendant system component controls a
unidirectional clock signal that regulates data transfers to or from the
host device and a downstream pendant peripheral. A device identification
field associated with the data packet is incremented or decremented as
the data packet is forwarded along the pendant bus chain until it reaches
its destination.