Abstract: A line circuit is described which provides isolated power to a subscriber telephone line in a manner that produces a constant power characteristic over the normal range of telephone line loop resistance. The isolated feed characteristic of the present invention simplifies protection against lightning and other transients. The constant power characteristic limits power dissipation under short loop, i.e. low resistance, or short circuit conditions yet allows enough current flow under short loop conditions to activate the voice level reducing varistor in the telephone sufficiently to prevent excessive loudness. This eliminates the need for additional circuits at the telephone central office for detecting short loops and for providing voice frequency (VF) level attenuation under such conditions.

Abstract: During the formation of an optical fiber coil on an elongated rotationally symmetrical support element, the tension applied to the optical fiber as it is being wound into the coil is gradually or incrementally decreased as the superimposed layers of the optical fiber coil are being deposited on top of one another in the radially outward direction. Thus, the force applied to the fiber as it approaches the take-up location on the support element to achieve the desired longitudinal tension in the optical fiber may decrease from the range substantially betwen 150 to 300 grams initially to the range of substantially between 50 and 70 grams as the optical fiber coil nears completion. An apparatus for winding the optical fiber coil includes the arrangements needed for monitoring the progress of the winding operation and for adjusting the various parameters of such operation accordingly. An optical fiber coil arrangement obtained in this manner has very low optical losses even at extreme temperatures.

Abstract: To allow PBX or key telephone systems, which are connected to dial pulse central offices, to use discount rate long distance, remote banking, and other services that require DTMF dialing, the system CO interfaces are equipped with a DTMF generator for tone dialing and a loop control relay for pulse dialing, which are under the system control. The user initiates dialing which is in pulse mode by default. After completing the dialing sequence into the CO, by pressing a designated button all other numbers dialed will be in DTMF. After the user hangs up the process may be repeated again. This feature can also be provided in conjunction with auto dialing.

Abstract: A ringer employs a low-cost miniature transducer, having a reverberant cavity, mounted in a cylindrical housing which has a second reverberant cavity in front of the miniature transducer. A very large acoustic output power is achieved when the ringer is employed in known cordless telephones, using the conventional available 3.9 volts battery. The ringer, due to its small relative size, may fit in the limited space inside a cordless telephone portable unit without costly tooling modifications. It is also suited for other uses, including for employment in compact one-piece telephones. The ringer is substantially more compact, louder in sound level, more pleasant sounding than known devices, and operates from a substantially lower DC voltage source.

Abstract: An improved cellular mobile radio telephone system is described wherein the switching matrices used to provide communication paths between subscribers is also used to provide paths for carrying control information between a network control and the various transceivers, receivers and transmitters at cell sites. Additionally, statistical multiplexers are provided at the cell sites for multiplexing control signals for many transceivers, receivers and transmitters onto the transmission facilities connecting the cell site with the network control system. At the network control system, apparatus is provided to reformat and packetize control signals from many statistical multiplexers and present the reformatted, packetized information to a network control processor.

Abstract: An optical fiber cable employs a central strength member fabricated from a dielectric material which member is surrounded by a plurality of peripheral tubes each having a hollow loosely containing an optical fiber. The tubes are fabricated from a plastic having embedded therein glass fibers to offer additional strength to the tubes to thereby permit a substantial reduction in the cross-section of the central support member which now serves in conjunction with the tubes to provide strength to the overall cable.