Apparatus and method to minimize power usage by electronic devices. In
a particular disclosed example, the battery power of a remote handset is reduced
by extending the sniff period of a cordless telephone when the remote handset is
remote from its base unit and the user is not likely to use the cordless telephone
(e.g., when away from the house or when asleep). A low power mode module causes
the electronic device, e.g., the remote handset of a cordless telephone, to remain
in an extended low power STANDBY mode, or to extends the period of the periodic
transition to a receive only STANDBY mode to check status registers at the base
unit, at appropriate times. In one embodiment, a low power mode table contains
entries defining periods of time during which the remote handset may transition
between the low power STANDBY mode and the receive only STANDBY mode. The remote
handset transitions to a fully powered transmit/receive (TDD) ON mode, e.g., in
response to an appropriate status condition, or in response to the activation of
a particular button or sequence of buttons at the remote handset. The extended
STANDBY mode may alternatively be activated in response to input from an external
device such as a home security system indicating that the user of the cordless
telephone is not willing or able to answering any incoming telephone calls. The
extended STANDBY mode may also be entered upon determination by the cordless telephone
that the telephone line is already in use by another extension (thereby rendering
unlikely any receipt of a ring signal condition from the base unit).