Abstract: A caller-ID telephone station having a caller-ID based directory of telephone numbers automatically adapts its directory to compensate for a change to the area code in which the telephone station is located. The caller-ID telephone station stores the area code for all incoming caller-ID telephone numbers along with each telephone number received. The telephone station also stores its home area code. This home area code is inputted by a user during an initialization step when the telephone station is first installed, moved to a different area code or the station's locale is changed to a different area code. In response to a request from the user for dialing a telephone number entered into the directory, the telephone station compares the stored area code received as part of the caller-ID telephone number with the stored home area code and determines from this comparison whether to include or omit the received area code as part of the dialed telephone number.

Abstract: Telephone line status indication is improved by making measurements of the differential voltage across the Tip-Ring terminals of a telephone set. The telephone set is connected to a telephone line which is shared with other parallel-connected sets. The measurement of differential line voltage is made time the set changes state (i.e., between on-hook and off-hook). The maximum magnitude of one of the last three measurements is stored to represent the state, and is arithmetically averaged with the maximum magnitude of one or the last three stored for the oil-hook state to create a reference voltage. The reference voltage is updated each time the telephone set changes state and is continually compared with the present differential line voltage to determine which one is larger A light-emitting-diode on the telephone set indicates that the telephone line is in use whenever the reference voltage exceeds the measured differential line voltage.