Abstract: Telephone calls are handed off from a wireless network to a wireline network under the control of a subscriber. When at a given location, the subscriber enters the directory number of the wireline terminal (typically the closest) to which a future wireless call is to be transferred. The entered directory number is then stored in memory in the subscriber's wireless terminal with the current location of the subscriber as determined by a satellite-based global positioning system (GPS) for future use. If the subscriber wants to transfer a call to a wireline terminal, the subscriber selects a transfer handoff key on the subscriber's wireless terminal. After the subscriber's location is determined using the GPS, it is then determined if a directory number (DN) of a designated wireline terminal has previously been entered and stored in memory for the subscriber's present location.

Abstract: Voice mail, email, fax and personal calendar systems are integrated allowing for the automatic updating of voice mail and email responses to received telephone calls and emails indicating that the receiver of the telephone call/email is out of the office, temporarily unavailable, etc. For received telephone calls, a determination is made as to whether the call was received during or outside of normal working hours, and if the person receiving the call is still engaged beyond a previous entered time period for providing an appropriate message to the caller. The determination is also made as to whether the received call is an “inside” or “outside” call, e.g., originating within or outside of the office or organization being called, and a predetermined response is provided depending upon where the call originated.

Abstract: A ringing detector circuit for use by the deaf which may be connected between the tip and ring conductors (11, 12) of a subscriber set to cause an incandescent lamp (40) to flash to half brightness when ringing voltage is applied to the line. Closing a manual switch (22) allows the lamp (40) to burn at half brightness when the phone is not ringing and to flash to full brightness when the phone is ringing.

Abstract: A negative impedance circuit comprising a level shifter and a current mirror, includes calibration circuitry for adjusting the negative impedance to provide the precise amount of current required to compensate for current drain caused by a known impedance at varying voltage levels. A divider/multiplier circuit is connected to the line which has the known impedance and provides a signal which is directly proportional to the voltage level on the line to the level shifter which, in turn, provides a corresponding control current to the current mirror. The current mirror provides a proportional current to the line current supplied by the current mirror and may be measured at a calibration resistor and the divider multiplier circuit may be adjusted to the appropriate ratio until the exact amount of current required to offset the drain to the precision resistor is provided by the current mirror.

Abstract: An impedance/admittance measuring circuit generates an output signal which is representative of the real or imaginary part of the impedance or admittance of a connected load. An excitation signal comprising a square wave having a fixed magnitude is generated and applied to a load. The response signal resulting from the excitation signal is filtered by a two pole bandpass filter (106). The filter output signal is used to control the excitation signal generator (101, 102) such that an oscillatory feedback loop is formed. By controlling the load connection and the phase relations between the excitation signal and the filter output signal, the magnitude of the output signal is representative of the real or imaginary part of the impedance or admittance of the connected load (103).

Abstract: An electronic loop identification circuit identifies loaded and nonloaded customer telephone loops. The loops can then be segregated to allow separate balance networks to be used for hybrid circuits which connect the customer loops to a digital switching office. Separate balance networks for loaded and nonloaded loops improve singing margin on those loops. An impedance measuring circuit (214) measures the real part of the impedance of a connected loop which is compared to a reference signal. If the real part of the loop impedance is greater than the reference signal, a loaded loop is identified; and, if the real part of the loop impedance is less than the reference signal, a nonloaded loop is identified. The circuit includes a self-calibrating arrangement which connects a reference impedance (209) to the impedance measuring circuit so that a capacitor (304) held reference signal can be set before each loop identification operation.

Abstract: A conference circuit (150) is disclosed for use in a telephone switching system (100) to provide communication among three or more subscriber stations (101, 102, 103). The subscriber stations (101, 102, 103) are connected to a plurality of ports (P0, P1, P2) of the conference circuit via communication lines (104, 105, 106) and a switching network (130). Amplification circuitry (210, 211, 212) connected to the ports (P0, P1, P2) provides input signal amplification to assure adequate transmission quality. A sensing circuit (220, 221) detects signals generated by subscriber station transitions and generates timed control signals to adjust the magnitude of amplification of input signals from the subscriber stations (101, 102, 103) for a predetermined period of time. Circuits (S1, S2) which supervise the states of junctor circuits (121, 122) connected to the conference circuit (150) provide for further gain control of the amplification circuitry (210, 211, 212).