Wireline interface for cellular telephone

Abstract

A wireline interface permitting a cellular telephone transceiver to originate and receive calls using both cellular and wireline services. The invention permits a subscriber unit to operate as a standard cellular telephone when it is disconnected from a land-based telephone line, and as both a full-featured telephone and a full-featured cellular telephone when it is connected to a wireline. A wireline interface circuit provides on/off hook, calling identification, and audio signal conversion functions on the wireline signals. A duplexed audio switch permits the audio signals provided to and from a cellular-type handset to be connected either to the cellular transceiver or to the wireline interface adapter, under control of the user. As a result, any handset-provided functions such as speed dialing or hands-free operation are available for use when operating on a wireline circuit as well as when operating on a cellular radio link. Call waiting is implemented between the cellular and wireline interfaces, so that the user may hold a wireline call when a cellular call is incoming, as vice versa. With automatic or semi-automatic call forwarding of the cellular line, permits the user to be accessed through a personal telephone number, regardless of whether the unit is in cellular or wireline mode. In addition, any calling identification information made available during a wireline call may be provided to a display on the handset.