A subscriber unit of a time division multiple access (TDMA) radiotelephone
system is, from a power consumption standpoint, reconfigured in each time
slot of a TDMA frame to a power consumption tessellation in which
subscriber unit circuit components not needed for communication signal
processing in that time slot are powered down, and other components are
powered up.
Some circuit components are powered down by switching their power supply
circuits. In order to minimize the extent of circuitry that must be
provided to distribute power consumption control signals, other techniques
(which utilize circuitry provided for other purposes), such as clock
frequency control or power down commands, also are utilized to modify
controlled circuit component power consumption without actually
controlling power supply circuits. Loop connection length between the
subscriber unit and the subscriber's telephone set, or other terminal
equipment, is limited to a length which is much less than the length of a
radio link on which the subscriber unit operates. Programmable ring
frequency logic controls the frequency of a ringing signal generator, and
a high frequency ring control signal is switched on and off in the cadence
of ringing operation. Also an expansion header is provided to enable
serving plural subscriber loop circuits with the same radio equipment for
reducing per line power consumption.
