Abstract: A distributed processing telephone system for providing "plug-and-play" capability. In particular, a key telephone system comprises a plurality of telephone sets. Each telephone set is coupled to a least one common communications channel, or telephone line, and includes at least one tunable RF modem. There is no key service unit (KSU). That is, the system is KSU-less. Resources of the telephone system are allocated using a peer-to-peer protocol. For example, as each telephone set is newly added to the system, the new telephone set adaptively determines its own allocation of resources, e.g., intercom numbers, etc. During operation, each telephone set requests the appropriate resources from its peers.

Abstract: A distributed processing telephone system for providing "plug-and-play" capability. In particular, a key telephone system comprises a plurality of telephone sets. Each telephone set is coupled to at least one common communications channel, or telephone line, and includes at least one tunable RF modem. There is no key service unit (KSU). That is, the system is KSU-less. Resources of the telephone system are allocated using a peer-to-peer protocol. For example, as each telephone set is newly added to the system, the new telephone set adaptively determines its own allocation of resources, e.g., intercom numbers, etc. During operation, each telephone set requests the appropriate resources from its peers.

Abstract: A communication terminal device having a line voltage detection circuit 6 connected in parallel with telephone lines 2 is characterized that when either of a built in telephone set 4 or an auxiliary telephone set 5 is off-hooked and then the hook detection circuit OH1/OH2 of the that telephone set 4/5 becomes on-hooked, the true on-off-hook states of that telephone set 4/5 and the branch telephone set 3 are judged by referring to the hook detection circuit OH1/OH2 and the aforementioned line voltage detection circuit 6 after a predetermined time period T has elapsed.The communication terminal device such as a facsimile device and the like having the arrangement described above is able to detect the off-hook/on-hook state of a built in/auxiliary telephone set connected to the telephone lines in parallel with a branch telephone set without mistake even if the branch telephone set is off-hooked.

Abstract: This invention relates to a cellular telecommunications systems that utilizes encryption and employs encrypted seed number signals to make it more difficult to make unauthorized cellular telephone calls.

Abstract: An apparatus that after a time period settable by the user automatically returns an off-hook telephone to an on-hook condition. This apparatus thus electrically hangs up a telephone handset that is inadvertently left off-hook and allows normal handling of outgoing and incoming calls at other telephone extensions and in some embodiments, even allows calls to ring-in to the telephone having the inadvertently off-hook handset. The apparatus also senses when the inadvertently off-hook handset is returned on-hook and rapidly restores the automatic-return-to-an-on-hook condition switch to normal operation.

Abstract: A device for detecting an operation state of a telephone hook switch in a telephone includes a timer, a controlling circuit, a counter and a table electrically interconnected. According to the present invention, the abnormal signals generated by the hook switch cannot be accepted by an exchange or even if the signals are accepted by the exchanger, the mute function of the telephone will be utilized to make the users unable to listen to each other.

Abstract: A simple and inexpensive telephone exclusion or privacy device. A conference feature is and am indicator light showing when the line is in use are also provided. The basic exclusion or privacy circuit includes only eleven components, thereby providing a very low cost device. The circuit includes a diode bridge with a Silicon Controlled Rectifier (SCR) connected across the midpoint of the bridge circuit. A resistor in series with the SCR limits the amount of current which the SCR can draw from the telephone line. A Zener diode in series with a resistor is connected between the anode and the gate of the SCR and a resistor in series with a capacitor is connected from the gate of the SCR to the second side of the bridge circuit i.e. to the point where the cathode of the SCR is connected.

Abstract: A telephone connection is established between a pushbutton telephone set and one of telephone lines through a pushbutton telephone set unit, a speech highway, and a telephone line unit. When one of line and extension keys of the pushbutton telephone set is pressed by the user during the telephone connection, a CPU in a control unit determines whether the telephone connection is being made based on the period of time that has elapsed after the pushbutton telephone set has captured the telephone line. If the telephone connection is being made as determined by the CPU, then the CPU controls a time switch circuit according to hold function data stored in a RAM to connect the telephone line unit to a hold tone generator through the speech highway, thus holding the telephone connection. Thereafter, the CPU captures a telephone line corresponding to the depressed one of the line and extension keys.

Abstract: A connector unit (21) for automatically terminating a digital data services (DDS) line whenever a mating modular plug (30) is not inserted into the connector. The connector utilizes a switchable DDS jack (25) that mates with the modular plug (30) for connecting a data-transmit line and a data-receive line of a DDS network (41) to a customer's equipment (45). The connector unit has a maintenance termination circuit (40) with terminating impedances (r, r1, C and C1) and diodes (D and D1). When the plug and jack are not engaged, the maintenance termination circuit is connected to the data-transmit and data-receive lines via the normally closed jack contacts (33 and 34). As the plug and jack are engaged, the plug abuts against and, as movement continues, increasingly opens the jack contacts, causing the maintenance termination circuit to be disconnected from the customer's equipment and to be connected to the DDS network.

Abstract: A telephone extension controller for permitting controlled access of telephone line from one of a given number of extension telephones coupled thereto when each extension telephone is controlled with the same comprising a lock-out circuit adapted to be coupled to a ring wire or a tip wire, the lock-out circuit further adapted for allowing a selected extension telephone of a plurality of extension telephones coupled to a telephone line to control and prevent the other extension telephones from accessing the telephone line when its switch hook is raised, the lock-out circuit including an optoisolator photo-coupled Darlington transistor having a conducting section and a photo-activated section and a Zener diode coupled in series with the conducting section of the Darlington transistor and coupled in parallel with the photo-activated section of the Darlington transistor.

Abstract: A communication unit connectable in parallel with other communication equipment to a two-wire telephone line communicates through the telephone line and a detector detects a voltage across the two-wire telephone line. A command unit commands communication by the communication unit and a controller controls the communication by the communication unit according to the detection by the detector and the command by the command unit.

Abstract: A diverter interfaces first and second telecommunication lines from first and second telecommunication sources, respectively, with a third line coupled to a station set. The diverter includes separate line and set monitors and a control unit. The line and set monitors monitor and detect predetermined selective signals such as (a) ringing signals propagating on the first and second lines, and (b) line access codes, flash hook, and line change requests signals generated by the station set. In response to the detected predetermined selective signals, the line and set monitors generate first, second, and third output control signals representative of the predetermined selective signals on the first, second, and third lines, respectively, to the control unit.

Abstract: A ring trip deciding method in a ring trip circuit detects voltage change in the on-hook state and the on-hook state of a terminal when the terminal such as telephone set connected to the telephone line is called.

Abstract: A security node disposed in the telecommunications network connecting calling and called parties transforms information (which can be voice, data, facsimile, video and other types of calls or messages) encrypted in a first format to (a) encrypted information in a different format or to (b) non-encrypted information, and vice-versa. The node is accessible from any location connected to the network. By routing calls or messages originated by the calling party and destined for the called party via the security node, and providing appropriate control signals to the node, the information may be encrypted only over a portion of the transmission path between the parties, and clear over the remainder of the transmission path. Alternatively, the information may be encrypted in different portions of the path using different encryption algorithms.

Abstract: A communication apparatus includes an extension-line connector to be connected to a private branch exchange, an external-line connector to be connected to external lines, and a plurality of independently operable communication control units. When an attempt to perform a communication with an external station is made in a situation in which the external-line connector is already being used for a communication with another external station, the attampted communication with the external station is effected via one of the plurality of communication control units which is not in use, the extension-line connector, and the private branch exchange.

Abstract: A telephone line bridging sensor circuit is provided which provides a variable output frequency signal to a microprocessor for measuring and storing the frequency count on a periodic basis. The circuit includes an isolation transformer to isolate the audio component of the telephone line from the sensing circuit. The loop current present in the telephone line is rectified through a full wave diode rectifier and the output of the rectifier is filtered and regulated to provide an input voltage to an astable, voltage controlled oscillator. As the current on the telephone line varies, the input voltage to the oscillator also varies a proportionate amount causing the output frequency of the oscillator to change accordingly.

Abstract: A control and switching unit used with at least two devices for transmitting information or voice communication over telephone lines. The control and switching unit is provided with a series of relays to ensure that only one of the devices receives or transmits information at any one time. A timing circuit is utilized such that if one of the devices is a telephone, the second device would not be able to gain access to the telephone line if the telephone is ringing. Additionally, if the telephone is in use, the secondary device, such as a modem, could be selected and this secondary device would gain access to the telephone line after the use of the telephone has been discontinued.

Abstract: A voltage breakdown circuit is connected in series between telephone answering machine circuitry and a telephone line. The voltage breakdown device becomes conductive only when the voltage across its terminals exceeds a predetermined level. If a telephone connected to the same telephone line as the answering machine circuitry is placed in the off hook condition, the voltage across the voltage breakdown device falls below the threshold level and the answering machine circuitry is effectively cut off from the telephone line. The voltage breakdown circuit is also useful in defeating automatic recording equipment placed in parallel with a telephone. Such automatic recording equipment is automatically disabled whenever the voltage across the tip in ring terminals of a telephone line is above a predetermined level.

Abstract: A call appearance reservation arrangement where any number of the call appearances of a directory number are reservable, and where a reservation type is defined for the directory number such that calls to and from the reserved call appearances are processed in accordance with one of a number of possible reservation types, such types for example including: (1) origination only, (2) termination only, and (3) origination and priority termination only.

Abstract: A controller couples a modem or facsimile device to a telephone trunk or line and also connects another instrument or communications device to the same line so that the line can be shared without danger of the two devices interfering with one another. The line is divided into separate branches to connect to the two devices. Each branch has a line relay that senses line current in the tip and ring conductors of the respective branch when line current is present. A holding feature accommodates dial pulse interruptions in the line current and/or pulse signalling.

Abstract: A multiple mode switching device is disclosed which is capable of interconnecting either one of a first or second apparatus, such as a controller, to a third apparatus such as a modem or a business terminal, and which is capable of operating in a first mode in which either the first apparatus or the second apparatus can be manually selected for connection to the third apparatus; in a second mode in which either the first apparatus or the second apparatus can request connection to the third apparatus and will retain such connection as long as needed; and in a third mode in which a selected one of the first apparatus and the second apparatus has priority and will always obtain and retain connection to the third apparatus when needed. First and second manually controlled switches are provided for selecting the mode and the desired apparatus in the manual mode. Logic circuitry is provided for controlling the operation of the switching device in the second and third modes of operation.

Abstract: Automatic telephone line sharing apparatus is disclosed that will only allow one telephone set or other communication device to be connected to a shared telephone line at a time. Circuits in the apparatus sense when a first one of a plurality of telephone sets or other communication devices is connected to a shared line and causes switches to be operated disconnecting the other telephone sets and devices from the line. When the first set or device disconnects from the shared line, this is sensed and the other sets or devices are automatically reconnected to the shared line. This automatic operation insures exclusive line use by blocking line access by other telephone sets or devices sharing the common telephone line.

Abstract: An interface circuit for interconnecting an analog telephone device with a digital telephone system includes an independent power supply (58) for driving the loop termination on an analog telephone device (22). An impedance matching circuit (54) and a summing network (42) are utilized to both couple the signal from the analog telephone device (22) to the analog input of a key service unit (10) and match the impedance therebetween. A switch, (46) is provided to disconnect the analog port of a digital telephone device (12) that is compatible with the key service unit (10). When the analog telephone device (22) is in the off-hook mode, a switch control (52) opens the switches (48) and (50) of switch (46). The digital telephone device (12) is under the control of a digital transmission line (20) to maintain an analog interconnection in the key service unit (10). The analog telephone device (22) operates on an independent loop termination with an independent loop current.