Abstract: A multi-circuit emulating line card is installable in a single line card slot of the backplane of digital switch, and is configured to emulate the functionality of each of a plurality of digital switch line cards, respectively associated with plural digital subscriber circuits served by the switch. In the course of emulating these plural line cards, the multi-circuit line card provides connectivity between each digital subscriber circuit and a digital carrier communication link to plural digital subscriber loop circuits, such as BRITE cards of a remote terminal site. The line card of the invention also includes network and subscriber circuit-associated metallic link impedance simulation circuits for terminating a metallic test bus.

Abstract: A multi-circuit emulating line card is installable in a single line card slot of the backplane of digital switch, and is configured to emulate the functionality of each of a plurality of digital switch line cards, respectively associated with plural digital subscriber circuits served by the switch. In the course of emulating these plural line cards, the multi-circuit line card provides connectivity between each digital subscriber circuit and a digital carrier communication link to plural digital subscriber loop circuits, such as BRITE cards of a remote terminal site. The line card of the invention also includes network and subscriber circuit-associated metallic link impedance simulation circuits for terminating a metallic test bus.

Abstract: A multi-circuit emulating line card is installable in a single line card slot of the backplane of digital switch, and is configured to emulate the functionality of each of a plurality of digital switch line cards, respectively associated with plural digital subscriber circuits served by the switch. In the course of emulating these plural line cards, the multi-circuit line card provides connectivity between each digital subscriber circuit and a digital carrier communication link to plural digital subscriber loop circuits, such as BRITE cards of a remote terminal site. The line card of the invention also includes network and subscriber circuit-associated metallic link impedance simulation circuits for terminating a metallic test bus.

Abstract: A composite circuit card architecture conforms with a prescribed form factor for installation in a card slot and connection to a backplane of a multiple circuit card-supporting housing. Only a portion of the card is comprised of printed wiring board material, while the remainder, where no printed circuit components are installed, is a support substrate formed of a material other than that of said printed wiring board. Also, a front panel portion is formed of the material other than that of the printed wiring board, such as plastic integrally molded with the support substrate, thereby significantly reducing the cost associated with the conventional approach of making the entire card from printed circuit board material. At one communication link, such as a ribbon cable, may be coupled between the printed wiring board and at least one input/output port at the front panel.

Abstract: A composite circuit card architecture conforms with a prescribed form factor for installation in a card slot and connection to a backplane of a multiple circuit card-supporting housing. Only a portion of the card is comprised of printed wiring board material, while the remainder, where no printed circuit components are installed, is a support substrate formed of a material other than that of said printed wiring board. Also, a front panel portion is formed of the material other than that of the printed wiring board, such as plastic integrally molded with the support substrate, thereby significantly reducing the cost associated with the conventional approach of making the entire card from printed circuit board material. At one communication link, such as a ribbon cable, may be coupled between the printed wiring board and at least one input/output port at the front panel.

Abstract: To extend the transmission distance for basic rate integrated services digital network (ISDN) communications between a first site and a second site, the basic rate ISDN channel is demultiplexed onto a pair of half-rate digital subscriber loop channels, which employ an out of band maintenance channel to convey differential delay compensation information, but without modifying the framing structure of the transported channels, or requiring additional bandwidth for a separate framing channel. Halving the data rate, to increase the distance over which the basic rate ISDN channel may be transported, operates as a trade-off against loop loss, while still complying with ANSI standards.

Abstract: A unitary connector for providing a connection between a printed circuit board edge connector and a telephone line jack, wherein a busy-out line condition is indicated when the printed circuit card is removed from the connector according to the present invention. The connector includes a female printed circuit board edge connector and a female telephone connector, each having the appropriate resilient connectors therein and paths for conduction between the two respective connectors. Moreover, the printed circuit board edge connector includes a plurality of electrically independent resilient contacts arranged in opposing rows, wherein at least one contact of one of the rows engages the respective opposing contact in the second row. The two engaged contacts are connected to the appropriate telephone jack pin to provide a busy-out condition indication.

Abstract: A coin sorter and totalizer which easily can be adapted to count the coins of many different countries despite the use of different coinage systems in those countries. The coins are sorted mechanically according to size, and an electrical signal identifying the coin according to its size is produced. Two sets of terminals are mounted near one another so that connections can be made to them easily. Changing these connections will change the scaling of the coin identification signals in accordance with the value of the coin of that size in the country in which the totalizer is to be used. The connections can be changed by the use of jumper wires, or by connecting a pre-wired multiple circuit element such as a printed circuit board, an integrated circuit chip, or a pre-wired plug-in panel between the sets of terminals. The connection process is very simple because only one wire need be connected for each size of coin to be totalized.

Abstract: An ionization-type gas contamination detector, intended primarily for use as a fire detector, in which a substance which emits predominantly low-energy beta particles is used as an ionizing radiation source in an ionizing chamber. Rapid changes in ionization current, which indicate the present of a fire or smoke preceding a fire, are detected and an alarm is energized by a rate-of-change circuit in response to such changes. The output of the ionization chamber is amplified, and a level detector energizes the alarm when the amplified chamber output reaches a predetermined level. The output of the amplifier is adjusted relatively slowly to a reference level. In one embodiment, the amplifier output is adjusted to the reference level by the activation of a sample-and-hold feedback loop for a short period of time. In another embodiment, continuous feedback through a circuit with a relatively long time constant provides the desired adjustment.