Intercommunication method between portable units in TDMA cordless telephone system

Abstract

An intercommunication method between portable units in a TDMA (Time Division Multiple Access) cordless telephone system. In an embodiment of the present invention, it is determined whether a portable unit is positioned in the propagation area of a base unit upon an intercom request from the portable unit. A time reversal is then performed when the portable unit is out of the propagation area of the base unit. Time slots are designated for intercommunication between the portable unit and a portable unit to be called and an intercom call signal is transmitted in the designated time slots. When a called party responds to the intercom call signal, a speech mode is performed. Upon termination of the intercom call, the reversed time is reversed again to recover the original state. In another embodiment, it is determined whether a portable unit is positioned in the propagation area of a base unit upon an intercom request from the portable unit. Time slots are designated for intercommunication between the portable unit and a portable unit to be called when the portable unit is out of the propagation area of the base unit, and an intercom call signal is transmitted in the designated time slots. When a called party responds to the intercom call signal, the speech mode is performed.

Dependencies are inferred from the claim text.