Abstract: An office interface unit (OIU) transfers data and signaling between a telephone local exchange and distribution lines. Information from the telephone local exchange is contained in repetitive frames containing signaling time slots which each contain two distinct nibbles of information. The OIU translates each local exchange signaling channel into first and second internal signaling channels, each internal signaling channel containing information representative of one signaling nibble therein. This simplifies DSO time slot interchange in the OIU. In addition, each internal signaling channel is provided with at least one additional significant signaling bit thereby providing additional signaling states so that the OIU equipment can account for multiple types of telephone local exchange equipment easily.

Abstract: A subscriber set includes two line terminals, and electronic telephone set circuit, and a hook switch for switching the line current.

Abstract: A private automatic branch exchange includes a four-wire type extension modular jack for connection to a four-wire type analog key telephone set as an extension terminal device and for connection to both a two-wire type digital key telephone set and a standard two-wire telephone set as extension terminal devices. Event determining circuitry determines whether or not an event has been received and the kind of extension terminal device concerning the event and outputs a control signal accordingly. Analog/digital key telephone set interface circuitry makes a data signal exchange with an analog key telephone set or a digital key telephone set connected to the extension modular jack. Standard telephone set interface circuitry makes an analog signal exchange with an analog key telephone set or a standard telephone set connected to the extension modular jack.

Abstract: A digital telephone answering device (DTAD) that allows messages to be forwarded to certain internal mailboxes. Random access memory (RAM) is flexibly and dynamically controlled by a microprocessor or controller. Audio signals in the form of voice messages are digitized and stored in the RAM. Messages can be sorted and allocated to specific mailboxes and made retrievable by pressing a button assigned to that mailbox. Messages can also be moved or re-assigned from a common message area to a certain mailbox or mailboxes. Outgoing messages are also stored in RAM and can be of sufficient number to have an outgoing message correspond to each incoming message storage area. The normal message recording and message playback functions of the DTAD may be activated after the call has been answered on the receiving side.

Abstract: A pay telephone (10) is disclosed which comprises a front housing assembly (12) and a rear housing assembly (14). A rear board housing (16) is coupled to modules disposed within front housing assembly (12) through a pair of cables (48) and (50) coupled to an interconnect board (46) disposed in front housing assembly (12). Front housing assembly (12) engages rear housing assembly (14) on opposite vertical sidewalls of rear housing assembly (14) through the use of locking hooks (36a)-(36e) and locking hooks (42a)-(42e) and locking receiving slots (40a)-(40e) and locking receiving slots (52a)-(52e).

Abstract: A speech communication apparatus of the present invention includes, in addition to an echo canceller for canceling an acoustic echo generated in a hands-free speech space, a chirp signal generating unit and a training unit. The chirp signal generating unit generates a chirp signal adequate for initial training of the echo canceller. The training control unit enables the chirp signal generating unit to generate a chirp signal, when a predetermined condition for starting hands-free speaking is satisfied, and a chirp tone corresponding to the chirp signal to be output as a volume-amplified tone from the hands-free speaker. The echo canceller performs initial training of the echo canceller based on the chirp tone.

Abstract: A hands-free circuit includes a transmit noise level detector which detects a transmit noise level and a first comparator which compares the transmit noise level with a reference level. If the transmit noise level is higher than the reference level, the first comparator provides a control signal indicating a noisy state has been detected. In response to the control signal, a transmit audio level is attenuated. Further the attenuated transmit audio level is compared with a receive audio level by a second comparator which provides an output signal indicating either a transmit-mode or a receive-mode. In response to the output of the second comparator, one audio signal is attenuated.

Abstract: Sidetone in a four-wire telephone station set that is coupled to a two-wire telephone line through a four-to-two wire hybrid circuit is automatically and cancel the phase "to a predetermined value", set by incrementally adjusting a balancing impedance connected to the circuit until an optimum impedance match between the telephone set and line is achieved. Under software control, during idle intervals between dialed digits when a call is initiated, a microcontroller mutes the telephone transmitter and receiver on the telephone side of the circuit and substitutes for these components a tone signal generator to produce a sidetone signal that is applied to a full-wave rectifier and therefrom to a peak voltage detector to generate a sidetone envelope. Individual ones of several impedance balancing networks are then sequentially connected to the telephone side of the circuit and the sidetone envelope for each balancing impedance is digitally encoded and stored.

Abstract: Digital communication systems cover a wide range of applications with the provision of features. However, new features must be added for specific application areas. One such specific application area is trading with shares, currency, raw materials, etc.

Abstract: A power and signal transmission system performs a transmission of a power from a first communication device to a second communication device via a transmission path as well as a transmission of a signal between the first and second communication devices via the transmission path. The first communication device includes a high voltage power source and a first pair of active inductances each having a low DC impedance and a high AC impedance, through which the power from the high voltage power source is supplied to the transmission path, and the second communication device includes a DC/DC converter and a second pair of active inductances each having a low DC impedance and a high AC impedance, through which the power transmitted via the transmission path is supplied.

Abstract: A disposable sanitary pad and associated dispenser for covering portions of a telephone handset to protect a user from contact with those portions. The pads are contained within a dispenser assembly and are attachable to both the mouthpiece and the earpiece of the telephone handset by hook and pile fasteners. The dispenser allows a simultaneous placement of a pair of pads to the handset from an underlying supply of the same and includes a desiccant assembly for maintaining the pads in a dry condition.

Abstract: Disclosed are hands-free land-line and radio telephones comprising a public telecommunication network connection part for transmitting a signal from the transmission signal input terminal to the public telecommunication network connection terminal and a reception signal from the public telecommunication network connection terminal to the reception signal output terminal, a first voltage controlled attenuator for controlling an output of the microphone by a given loss corresponding to a first control voltage level, a second voltage controlled attenuator for controlling a reception signal by a given loss corresponding to a second control voltage input level, a first detection circuit for generating a rectified voltage proportional to a magnitude of an input audio signal by rectifying an output signal of the microphone, a second detection circuit for generating a rectified voltage proportional to a magnitude of an input audio signal by rectifying an output signal of the reception signal output terminal, a contro

Abstract: A telephone answering apparatus permits a called party to select between an automatic mode wherein a message is automatically played back to a caller without any action of the called party and a prenouncer mode wherein a message is played back to the caller when activated by the called party. The telephone answering apparatus includes a ring detector circuit connectable to an outside line and responsive to an incoming call on the outside line for producing a ring detected signal, a timer and driver circuit responsive to the ring detected signal for producing a playback signal and a manually actuatable answer switch. A mode switch capable of selecting one of the prenouncer mode and the automatic mode is connected to the timer and driver circuit, to the ring detector circuit and to the answer switch.

Abstract: A cellular phone securing device has a fixing unit and a flexible tube, a linkage rod and a phone securing mount. The fixing unit is provided with a horizontal slide board, and a vetical contact member and a pair of bolts. The slide board and the contact member are one way adjustably limited in place and the bolts are selectively attached to the underside Of the fixing unit. In mounting of the securing device, the slide board and the contact member are adjusted to abut against a windshield of a vehilce and the bolts are in abutment with the edges of outlets of a ventilation system of the vehicle whereby the bolts and the slide board and the contact member constitute a three-point supporting of the fixing unit. The phone securing mount is adhered to a flat place of the front console board of the vehicle.

Abstract: Disclosed is a circuit for providing an appropriate amount of on-hook loss in a digital loop carder transmission system serving telephone customers. The resistance of the customer loop is measured while the customer is off-hook and an amount of loss is added based on that resistance during the off-hook interval. A predetermined constant loss is then added to the appropriate off-hook loss when the equipment returns to on-hook status.

Abstract: A method where a telecommunication system records a message spoken by a caller and plays the recorded message to a human attendant for use in routing an incoming call without the attendant having to answer the incoming call. The system then responds to input from the attendant by playing the message to a third party to familiarize the third party with the call before the caller is removed from hold and the call is completed to the third party. In this manner, the first person that the caller speaks with has already listened to the message. The message is supplemented with additional voice messages or conversations as the call is handled by multiple parties. Wordspotting is used as the initial message is being recorded; if the wordspotting is successful, the recorded message is routed to a third party without any attendant involvement and the third party is familiarized with the call.

Abstract: Echo canceling method and apparatus for subtracting, from a mixed signal in which echoes produced from a plurality of reception signals are mixed with a transmission signal, a replica of the echoes in order to cancel the echoes in the mixed signal. The replica of the echoes are generated by the steps of selecting the reception signal which is leading in phase and producing a replica of the echoes from the selected reception signal by an adaptive filter. Generally, the replicas are produced by adaptive filters provided in one-to-one correspondence with the mixed signals.

Abstract: A telephone set includes an anti-sidetone circuit formed by a feedback loop having a filter in the feedback path. The feedback loop output is substantially equal to the signal produced at the set connection terminals by the microphone. Preferably the filter is composed of two sub-filters connected in cascade, formed of switched capacitors in an integrated circuit. An EEPROM control circuit can be included to permit easy programming during manufacture, to match a selected transmission line impedance.

Abstract: A headset amplifier, adapted for use with a voltage source such as a battery, includes a time-out-timer circuit for deactivating the headset amplifier after a first predetermined period of time and for reactivating the amplifier in response to a signal fed to an input port of the time-out-timer circuit.

Abstract: An automatically progressively-activated and reset "send-all-calls" (SAC) feature provides the following functionality. In response to receipt at a switching system of each call for a destination subscriber station that has the feature enabled, the system retrieves a stored specified period of time for which a call directed to the station is allowed to go unanswered at the station, and then shortens the stored specified period, thereby progressively hastening activation of SAC for a subsequent call. If the retrieved period is of nonzero duration, the switching system directs the received call to the destination station. If the retrieved period is of zero duration, or if the directed received call goes unanswered at the destination station for the duration of the retrieved period, the switching system redirects the call to a call-coverage facility in the manner of a standard SAC feature.