Abstract: Disclosed is a communications network for peripherals in a digital loop carrier transmission system. A broadcast STAR network is employed so that all peripherals receive any message which is broadcast by any of the peripherals. No peripheral broadcasts without clearance from the active communications hub. Two hubs can be provided to alternatively act as the active hub. Each peripheral includes a controller which transmits a request to send signal, multiplexes the request to send signal with an outgoing message, receives clear to send signals, and demultiplexes the clear to send signals from an incoming message.

Abstract: A transmission system comprises apparatus for the transmission of voice signals only, data signals only, or a combination of both voice and data signals in a multiplexed stream of eight bit time slots over a single, bidirectional digital channel for a point-to-point connection. In the combined mode, the encoded voice signals, using low bit rate voice encoders, are assigned to four bit positions of the eight bit time slot; the data signals are assigned to the remaining four bits. Up to two bit positions normally used for data may be used for signature bits, thereby identifying whether the multiplexed stream comprises voice signals only, data signals only, or a combination of both voice and data signals. Also, a minimum of one "1" bit per eight bit time slot is thereby guaranteed.

Abstract: The tip and ring leads (15,17) of a tip party transmission facility are reversed before connecting the separate channel units for the tip and ring party channels to bridge lifters (16,18) at the central office, thus permitting selective ringing. Tip party identification for billing is provided by a tip-party indicator (20) inserted in the tip party transmission path at the central office by grounding the tip conductor when needed. The need for rewiring the tip party telephone set is then eliminated by providing separate single party channel units.

Abstract: A simple and inexpensive direct current voltage level detector is shown which has a significant immunity against interfering alternating current signal components. The output of a standard analog threshold detector is successively sampled by clock pulses having twice the repetition rate of the frequency of the expected interfering alternating current components. By requiring two successive samples to be above the threshold of detection, immunity is provided against false detection due to temporarily exceeding the threshold level due solely to the positive excursion of the interfering alternating current components. Simple clock-driven flip-flops are used for the sampling and a simple logical AND gate is used to detect the successive samples.

Abstract: A subscriber loop carrier system is shown in which coin first and dial tone first pay stations can be serviced through the carrier system without modifying the central office. Coin supervisory states are detected at the central office terminal of the system, translated into unique cyclic codes for transmission through the system and detected at the remote terminal by reapplication of the coin supervisory states at the remote terminal. Coin first and dial tone first modes of operation are accommodated with simple option plugs.

Abstract: A digital transmission system is disclosed in which time slots in selected frames are reserved for supervisory signaling bits. These signaling bits can be used to represent a large number of supervisory states by assigning at least three bit patterns to each of two interleaved streams of supervisory bits. These bit patterns may include, for example, continuous ones, continuous zeros and alternating ones and zeros. A supervisory state encoder and decoder for these bit patterns are disclosed.

Abstract: A testing system is disclosed for telephone subscriber loops which are in part derived by multiplex facilities in what have come to be known as pair gain systems. In this testing arrangement, the local drop wires from the remote terminal of the pair gain system to the subscriber are separated from the carrier system itself and tested by connecting them to a separate metallic pair extending from the central office to the remote terminal location. Simultaneously, the carrier-derived portion of the subscriber loop is connected to automatic testing apparatus which sequences through a plurality of automatic tests for not only transmission characteristics of the carrier-derived channel but also tests for the ability of the derived channel to transmit supervisory information such as ringing, coin control and party identification information. The remote terminal of the pair gain channel is selectively terminated by a reflective or absorptive termination to assist in these testing procedures.

Abstract: A ring-trip detection circuit is disclosed which is suitable for use at the remote terminal of a pair gain system, i.e., a system designed to supply more than one telephone subscriber with loop service over a single pair of metallic wires. The ring-trip detector circuit comprises a simple filter and semiconductor threshold circuit which responds to subscriber loop currents to disable ringing signals when the subscriber goes off-hook. The detector circuits are powered entirely by the ringing signal itself and thus draw no power when in the inactive state and require no auxiliary powering source in the active state.

Abstract: A power supply for developing substantially constant average power in a variable resistance load (18) from an alternating polarity source (11) comprises an AC portion including serially connected capacitor means (12), and a DC portion including rectifying means (20) for providing a polarized signal to load resistance (18) and inductor means (17) for maintaining a charging current through a path including capacitor means (12). The constant average power mode obtains when the range of values of load resistance (18) is less than a network parameter determined from the frequency of source (11) and value of capacitor means (12).

Abstract: A detector circuit is shown for detecting off-hook and dial pulse signals in a telephone system which, under the control of a ringing relay, reconfigures itself to provide ring-trip detection. The detection circuit includes a bridge which is responsive to circulating loop currents, while at the same time unresponsive to longitudinally balanced currents, and a two-stage voltage level detector circuit. An RC timing circuit is included between the two stages to insure that the detector is unresponsive to short duration pulses and, at the same time, once energized, will bridge over short duration interruptions of detected pulses.