Abstract: A dial tone detection arrangement for a PBX which provides a dial tone detection notification feature to a calling party is disclosed. The disclosed arrangement relieves the calling party from the burden of aurally monitoring the receiver of a station while waiting for receipt of central office (C.O.) dial tone. The dial tone detection notification feature is advantageous under conditions where the calling party places a call to a called station served by the C.O. and experiences extensive delays, e.g. 30 minutes, in the receipt of C.O. dial tone. The dial tone detection arrangement utilizes an algorithm to establish a connection between a dial tone detection circuit of the PBX and a trunk port connected to a C.O. via a switching network. The dial tone detection circuit monitors the C.O. via the trunk port for the presence of dial tone indicative of C.O. availability. The calling party may now go "on-hook" and await a notification at the calling station indicative of the detection of dial tone.

Abstract: This Inter-Exchange Carrier Access arrangement uses the Automatic Number Identification (ANI) capability of the central switching office to eliminate the need for the customer to dial an authorization code when accessing an inter-exchange carrier via a facilities reseller telephone communication system. The central switching office transmits the calling party identification (ANI) digits to the facilities reseller telephone communication system when the customer dials the remote access code for the facilities reseller telephone communication system. These received ANI digits are compared by the facilities reseller telephone communication system with a list of authorized customers stored in memory. If a match occurs, the identity of the inter-exchange carrier preselected by the customer is retrieved from memory and the telephone communication system automatically outpulses the inter-exchange carrier access code to the central switching office.

Abstract: The integrated calling directory of the present invention eliminates the disadvantages of prior call directory arrangements by providing a software system which runs on a personal computer to automate the call directory and call origination function. The personal computer is interposed between an individual's telephone station set and the business communication system port circuit associated with the individual's telephone station set. The calling directory software both contains the individual's personal directory entries and has access to directory entries in the centralized business communication system data base which resides on an adjunct processor. These directory entries all contain called party identification data which includes information such as an individual's name, room number, electronic mail address, telephone number, type of terminal equipment associated with the called party, job title, etc.

Abstract: This invention provides an audible indication to a held party indicating when a call is removed from the hold state. Heretofore, when two parties on a call are in a talk state and a first party puts a second party on hold, the held party must aurally monitor the receiver on the station set for the first party's voice to detect when the talk state is resumed. The voice of the first party provides the only indication that the hold condition has been removed. This requires the held party to monitor the receiver for the duration of the hold state and prevents the held party from easily pursuing any other activities. The subject arrangement overcomes this problem by providing a "ring-ping" signal to the held party when the hold condition is removed. In particular, following the activation of the hold condition by the first party, the held party leaves the receiver off-hook and can then pursue other activities.

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 packet switching system is disclosed for transmitting variable length packets between system ports. Each byte of each packet has a special one-bit field for indicating whether the byte is the last byte of a packet. A "1" in this field specifies that the byte is the last byte of a packet and activates port control circuitry that changes the potential on a system control conductor to indicate that the system data bus is now idle and free for use by other ports.

Abstract: A voice-switched telephone circuit with center idle state improves bi-dirional gain control in loudspeaking telephones and thereby enhances the natural quality of interactive conversation. The voice-switched telephone includes: a transmit channel having a microphone and a three-state amplifier; a receiver channel having a three-state amplifier and a loudspeaker; and a hybrid circuit interconnecting the transmit and receive channels to a two-wire telephone line. The present invention is characterized by independent signal level detecting circuits for the transmit and receive channels. When the magnitude of the signal energy in the transmit channel exceeds a predetermined threshold, the transmit channel amplification is increased and the receive channel amplification is decreased by fixed equal amounts.

Abstract: Apparatus for and a method of inserting circuit switch information and packetized data into different time slots of a time division multiplexed bus. A memory having a location individual to each time slot is written with information specifying whether the time slot individual to each location is to serve the circuit switch information or the packet data. The readout of each memory location during the occurrence of it's associated time slot controllably effects the application of either the circuit switch information or the packet data to the bus.

Abstract: A silicon micro-transmitter chip is housed within top and bottom closures snap-fitted together by legs and catches on the two closures. The chip is mounted between two acoustic cavities in the closures by a plate part of a configured metal sheet having other strip parts extending through grooves in the bottom closure to its outside where the strips are bent to provide arms for surface mounting the entire device on a printed wiring board. The sheet serves both as a continuous strap for effecting such surface mounting and as an electrode for connecting a terminal of the chip to ground. Other terminals of the chip are connectable to the board by flat leads passing through other grooves in the bottom closure to its outside where they are bent for surface mounting purposes. The housing formed by the two closures includes an adhesive impregnated gasket for providing an acoustic seal between the two cavities as to which the air pressures therein are equalized by a vent hole in the plate.