Abstract: A conference call sound level balancing method and system for selectively muting a conferee whose sound environment is loud enough to dominate other conferees of a conference call. The method is operable on a system that includes a network-based conference bridge and a sound equalization platform that is coupled to each telephone of a conference call. If one telephone connected to the conference call has a higher noise level than the other branches of the call, thus making it so the other branches cannot obtain speaking privileges, a predetermined touchtone key is entered at the noisy telephone. The sound equalization platform responds by automatically measuring the ambient sound levels of the respective branches of the conference call and balancing the speaking privileges for the respective call branches of the conference call.

Abstract: An improvement in the transparency of personal telecommunications over the prior art is achieved by automatically placing a return call from a personal communications unit of a called individual in response to a call from a caller and alerting the called individual to the existence of the call placed to his personal number only upon an indication that the call from the calling telephone remains in progress. In one embodiment of the invention, the called individual associates his personal communications unit with a telephone channel, before his reception of any calls. Should a caller make a call to the called individual's personal calling number, the telephone network causes the transmission of an actuation signal. In response to the actuation signal, the personal communications unit places a call to a predetermined number over a switched telephone network using the aforementioned associated telephone channel.

Abstract: A ring-trip detector circuit is disclosed which detects a subscriber off-hook condition in the presence of a ringing signal. The ring-trip detector employs substantially all low-voltage components which enables it to be fabricated using integrated circuit techniques with the resultant cost and space-saving advantages inherent therein. The ringing signal is disabled upon detection of a DC component which is present in the telephone loop only when the subscriber goes off-hook. This circuit detects the DC voltage component across a resistor (20) in series with the ringing source (19) and the telephone loop (12, 13). The voltage across this resistor (20) is converted by resistance networks (23, 24) into two relatively small currents that are fed to low impedance points (25, 26). A difference current is formed therebetween, which is filtered (31, 45) to remove AC components, and compared with a threshold current (29, 46). Ring-trip occurs when the filtered difference current exceeds the threshold.

Abstract: A protector unit (30) for protecting tip-and-ring conductors of a telephone loop includes a pair of protector assemblies (40-40') which are supported within a common housing 932). A voltage protection subassembly (42) is connected electrically to a ground subassembly (44) for causing current associated with excessive voltage surges to be conducted to ground. Each protector assembly includes a heat coil subassembly (50) mounted on a dielectric half-base (51), together with a central office pin (57). The heat coil subassembly includes a line pin (61), an eyelet (62), disposed concentrically about the line pin and releasably secured to one end of the line pin in an initial position by a fusible bonding material, and a resistance wire (69), wound about the hub of the eyelet. One end of the wire is welded to the eyelet, and the other end is welded to the central office pin to establish a direct current path between the line pin and the central office pin.

Abstract: In order to provide push-button telephone service to those telephone systems not equipped to respond to multifrequency dialing signals, it is necessary to convert push-button dialed digits into conventional dial pulses. A pulse train consisting of make and break intervals representing the dialed digit is electronically converted (107) into a corresponding series of make and break intervals on the telephone line (102, 103) by switching (106, 108-1, 108-2) a pulsing transistor (101) that is in series with the telephone line ON and OFF. In order to keep the pulsing transistor ON during nondialing intervals and during each make interval, and not attenuate the voice signal, the pulsing transistor is biased by an adjustable current source (105). The current needed to bias the pulsing transistor ON is linearly related to the telephone line current flowing through the emitter-collector path of the transistor, and which varies considerably from station-to-station.

Abstract: A maintenance termination unit (10) comprises a voltage sensitive switch (30,50) connected permanently in series with each loop conductor (11,13) and an impedance termination unit (18) connected permanently across the loop conductors. Each voltage sensitive switch (30 or 50) comprises a triac (32) connected in series with a loop conductor (11 or 13), a capacitor (34) and resistor (36) connected across the terminals of the triac, and a bilateral switch (60) connected between one of the terminals and the gate electrode of the triac. In response to a signal having a voltage greater than the threshold voltage of the switch, the capacitor is charged to the threshold voltage, thereupon the capacitor discharges insuring that the triac is gated to the ON state.