Showing papers on "High-bit-rate digital subscriber line published in 1980"

Subscriber station for providing multiple services to a subscriber

Abstract: In order to provide multiple services to a subscriber from a telephone central office, receiving and transmitting cables, preferably each being a single fiber optic strand, are coupled between the subscriber and the central office. Multiple signals, such as telephone signals, television signals, digital data, and FM radio signals are multiplexed onto the receiving cable. These signals are demultiplexed at the subscriber station to allow individual utilization of the services by the subscriber. Control of the services is allowed by transmitting control signals such as telephone control signals and television and FM radio channel selection signals over the transmitting cable, along with the telephone conversations and data. Further, alarm signals can be sent over the respective cables for purposes of monitoring fire, health, and security.

Conferencing apparatus and methods for a frequency division multiplex communications system

Abstract: A conferencing apparatus for an FDM communications system employs a first available sideband for communication and a second sideband for signaling. Each subscriber in the system has dual receiving and transmitting equipment which enables a subscriber to communicate with any other subscriber. During such communication, a memory at each subscriber location may receive the frequency pair of one subscriber in a connection. Another subscriber desiring to be conferenced will receive the stored frequency pair from the subscriber who is not on proper frequency. This is implemented by a standby receiver and transmitter associated with each subscriber. Upon receipt of this information, the new subscriber can then tune his equipment to store the frequencies as received to enable the new subscriber to be incorporated in a conference mode. The received frequencies are also stored in the new subscriber memory and hence, any additional subscribers contacting parties to the conference will receive information regarding the elected subscriber who is communicating on his properly assigned frequencies to thereby enable a plurality of new subscribers to join in the conference.

Telephone system using pulse code modulated subscriber lines

Abstract: In an all-digital telephone system for communication between a central office and widely scattered subscriber locations, means are disclosed for carrying digital service from the central office to various distribution locations over T1-type equipment and from the distribution locations to subscriber locations over ordinary two-wire lines using time-shared bidirectional pulse code modulation. A salient feature of the system is the provision of "smart repeater" means which permit unidirectional or bidirectional access between any digital subscriber line and any channel of the T1 line under the control of the central office. Provisions are also made in the system for the transmission of slow-speed signals suitable for the remote reading information from sensing devices at the subscriber locations and for the remote operation of suitable devices at the subscriber locations.

New line code for digital subscriber loop

Abstract: A new line code is presented which may find applications in the future digital subscriber loop. The line code is well balanced and has a narrow frequency spectrum.

Installation for wireless transmission of telephonic communications with a number of radio channels inferior to the number of subscriber stations

Abstract: 1. Installation for the wireless transmission of telephone conversations, with several subscriber's sets (S1... S4), each having an identification signal, with a subscriber's line (L1... L4) respectively associated with each of the subscriber's sets, leading to a telephone exchange, and having an identification signal, with a number, less than the number of subscriber's sets, of radio channels (K1, K2) used alternately by the different subscriber's sets, with a transmitter (2) and a receiver (3), both respectively associated (at the subscriber's end) with each of the subscriber's sets, switchable to the different channels, with a transmitter (7) and a receiver (8) (at the exchange end), both respectively associated with each channel and connectable to the different subscriber's lines (L1... L4), with circuit means for transmitting the identification signal of a subscriber's line on which a call comes in, the identification signal of a subscriber's set from which it is intended to establish a communication, and the dialling pulses transmitted by the subscriber's set with the aid of signal frequencies outside the speech band, further with circuit means (320) at the exchange end for identifying a channel over which a call directed to a subscriber's set is supposed to be transmitted, and with circuit means (226) associated with the individual subscribers, which circuit means (226), in the rest state of the respective subscriber's set, switch the associated receiver (3) cyclically over to reception of the different channels and interrupt the switching-over upon reception of an identified channel, characterized in that a frequency (218, 309, 318, 209) below the speech band is used as the signal frequency, that both the identification signals and the dialling pulses are transmitted with the aid of phase-modulation of the signal frequency, exhibiting digital phase reversals (fig. 5), and that the said identification of a call takes place by means of a single control frequency (320, 210) modulated upon the respective channel, situated in the speech band, and associated with several subscriber's sets in common.

Circuitry for a digital telephone subscriber station

Abstract: 1. Circuit arrangement for the connection of additional equipment to a digital telephone station (DT) with units (codecs) for the conversion of the voice information in analog signals and vice versa, which are transmitted full duplex via a two wire remotely fed individual subscriber's line (TAL) and with a first line circuit (L1) as interface to the subscriber's line (TAL), whereby the information arriving at the line circuit is forwarded to an interface for the connection of additional equipment and the information arriving from the additional equipment is forwarded to the subscriber's line, comprising a second interface (L2) having a line circuit for the connection of additional equipment, which is identical with the first line circuit (L1) for the subscriber's line (TAL), whereby the information arriving on the subscriber's line (TAL) and appearing at the terminals (a/b) is forwarded to the terminals (a'/b') of the second line circuit (L2), with these terminals an internal line (JAL) for the connection of additional equipment of the digital telephone station (DT) can be connected, the information transmitted from the additional equipment via the internal line (JAL) appearing at the terminals (a'/b') of the second line circuit (L2) is also retransmitted via a processor (VE) to the terminals (a/b) of the first line circuit, whereby the processor (VE), which is used for receiving, evaluation and generation of the received information and the information to be transmitted (for example speech information, signalling, addressing), prevents the retransmission of information, which is exclusively used on the internal line (JAL).

Signalling arrangement for telephone equipment

Abstract: Each of a number of remote subscriber telephones is connected through its own pair of lines, including ground lines, to a central office in the usual way. Each of many or all of the subscriber telephones has near it a special subscriber end equipment for doing a local job and connected across the related subscriber telephone. In the central office where the ground lines merge into a ground line going to one side of the standard direct current battery, supplying the remote subscriber telephones, there is a modulator in series in the ground line and effective to vary the voltage across the regular line pairs at a frequency or frequencies other than the voice frequency range but effective to actuate all of the special subscriber end equipments.