Abstract: A communication system is comprised of two or more circuit pack modules mounted onto a mounting apparatus. Each circuit module includes a plastic housing which holds a circuit board mounted therein. An equipment cabinet is formed by mounting a circuit module at each end of the mounting apparatus and utilizing a surface of each circuit module, respectively, as a side of the cabinet. A top panel of the cabinet mounts to the mounting apparatus and circuit modules and covers the circuit modules and any space therebetween. A front panel mounts to the top panel and circuit modules and serves as the front cover of the cabinet.

Abstract: A computer-controlled cordless telephone system having a base unit and a dset unit provides for increased functionality in communications between the base unit and the handset unit, and also provides a controlled power-up/power-down mode of operation for the handset unit. Increased functionality is achieved by employing a message format for control signals transmitted between the base unit and the handset unit in the form of frequency shift keyed (FSK) signals which include a data field. This data field may be in the form of either opcode data or digit data, thereby allowing for many different commands or functions. Power to a computer, a receiver and certain other selected circuitry in the handset unit is controlled to minimize power consumption when the handset unit is in an out-of-cradle-and-standby state. Power to other nonessential circuitry in the handset unit is turned completely off during this state.

Abstract: A data transmission flow control arrangement for controlling the flow of data packets to a network as tramsmitted by one or more data transmitting and receiving devices via an interface is disclosed. The disclosed flow control arrangement provides circuitry in the interface responsive to the storage capacity of a buffer included in the interface. If the buffer contains sufficient space to store a data packet of maximum length, data transmissions continue unencumbered. However, if the buffer contains insufficient space to accomodate a data packet of maximum length, the specialized circuitry of the interface responds to this condition and applies a signal to all of the associated transmitting and receiving devices of the interface. The jamming signal simulates the conditions associated with a busy network and therefore, inhibits the transmission of data from any of the associated transmitting and receiving devices.

Abstract: The connector assembly includes (1) a pair of connectors (300,300') for respectively terminating the individual conductors of a pair of multiconductor cables (200,200') and (2) a pair of adapters (500,600) that are respectively electrically connected to the connectors. The adapters come in different configurations and are user interchangeable to permit connection to external connectors having particular configurations.

Abstract: A coin operated telephone station is provided with apparatus for detecting hen a called party has answered a call (initiated at the coin operated telephone station) by the measurement of incoming signal energy on the telephone line. The apparatus includes hardware and software that cooperate in providing efficient and reliable detection of called party answer for the purpose of accurately charging telephone users. A microprocessor samples the output from each of three specialized energy detectors every 20 milliseconds to determine whether called party answer has occurred. The energy detectors include: (1) call progress tones in the frequency band 200-700 Hz approximately; (2) special information tones; and (3) broadband energy in the frequency band above 200 Hz. Additionlly, the time duration of the call progress tones and the quiet intervals between them are measured and used in the answer detection process.

Abstract: An interface circuit is described for interconnecting a packet switched system to a circuit switched system which enables a uniform dialing plan to be utilized to establish intra-system or inter-system connections. This is accomplished by assigning each terminal of the packet switched system a unique terminal address similar to the extension number used for terminals of the circuit switched system. The interface also distinguishes data call set-up requests from other control commands received from the packet switched system.

Abstract: An FSK demodulator of the differential type is arranged to provide two versions of an input FSK signal that, relative each other, (1) have a linear phase shift versus frequency characteristic and (2) are phase shifted by 90 degrees at a center frequency halfway between the upper and lower FSK frequencies. The linear phase shift is provided by an N sample delay element, while a constant phase shift circuit which includes a K factor gain element provides the 90 degree phase shift. By virtue of this arrangement, the demodulator characteristics can be adaptively varied and the demodulator tuned simply by changing the value of K. A similar adaptive technique is applied to a threshold detector arranged to position a threshold midway between the extremes of an input signal.

Abstract: There is disclosed an arrangement which enables a single modem port to be used for either synchronous or asynchronous data transmission, with no manual changes required. The modem determines whether the incoming call is synchronous or asynchronous by detecting the presence (or absence) of SYNC characters in the data stream immediately after handshaking. Once a determination has been made, the modem options itself accordingly for synchronous or asynchronous data handling. This arrangement eliminates the need for separate central office lines for synchronous and asynchronous data applications.

Abstract: The opening and closure of the contacts of a push-button actuated switch duces across impedance means a voltage which is stably high and low when such contacts are maintained closed and open, respectively. Bouncing of the contacts after their initial closures and openings produces superposition on the stable levels of such voltage of trains of impulses caused by such bouncing. A bistable semiconductor flip-flop is coupled to the impedance means to sense such voltage and to assume a "high" state and a "low" state only when the stable level of such voltage is, respectively, high and low and, further, the flip-flop receives a clock signal. A retriggerable semiconductor monostable multivibrator is coupled to such impedance means to be triggered by such impulses from its stable "off" state to its unstable "on" state which is repetitively renewed by repetitive retriggering of the multivibrator.

Abstract: A telephone handset comprises elongated complementary upper and lower housing members that mate at their perimeters to form a hollow handset housing. The lower housing member includes spaced transducer mounting positions, each of which accommodates both an individual transducer and a transducer mounting member for holding the transducer in the transducer mounting position. Each transducer mounting member is secured to the lower housing member and an upper surface of each enclosure inlcudes a recess for accommodating a bonding material. In addition, the upper housing member includes elements that extend into the recesses of the transducer mounting members when the upper housing member is mated to the lower housing member. The bonding material in the recesses serves to secure the two housing members together.

Abstract: A touch-sensitive device comprising a photoelastic screen having light reflecting edges and a unique light emitting/receiving module placed at two of the four corners of the screen advantageously determines the location at which a force is applied to the screen. Circularly and linearly polarized light focused into the photoelastic screen by the modules reflects off the edges of the screen and is returned to the modules where it is absorbed by a circular polarizer. The polarization of light passing through a point at which the screen is touched is changed thereby allowing these rays or signals to pass through each module's absorber. The location as well as the magnitude and direction of the force imparted to the screen by the touch is then determined from the changes in the signals that pass through the absorber.

Abstract: A line switch for a telephone set comprises a lever rockably mounted in the tand for the set and having as a rear part a plunger fin received in a slot passing through the stand to a handset cradle on its top. The lever has at its front a head carrying on its underside a pair of metal leaf springs of which front portions form spring contacts disposed over corresponding electroconductive pads on a printed wiring board mounted within the stand. The lever is biased by a torque spring to yieldably hold the upper part of the fin in the cradle. Removal and replacement of a handset from and to the cradle actuates the lever to produce engagement and disengagement, respectively, of the spring contacts with their corresponding pads. Such spring contacts and pads form, electrically speaking, a line switch adapted upon such engagement and disengagement, respectively, to produce a "short" and an "open" of terminations at the set of the tip and ring leads therefor.

Abstract: An adaptive equalizer for data signals is allowed to start up and train in a wholly decision-directed mode but is precluded from converging to an incorrect state by inhibiting equalizer updating for equalizer output values which fall within a predetermined null zone.

Abstract: There is disclosed a port communication method and apparatus for controlling system controller communications with port circuits of the system. The port communication apparatus generates commands to port module interfaces, interposed between the controller and port circuits, in a predetermined order and receives acknowledgement signals therefrom. Thereafter, the port interfaces concurrently collect data from the associated port circuits and transmit this data in response to a subsequent read command from the port communication apparatus. In one embodiment the port communication apparatus includes a programmable microcode routine which generates the commands using input parameters which are specified in various registers and in the microcode program call.