US 5,204,860 AGranted

Network terminating terminal apparatus for integrated services digital network

AssigneeNorthern Telecom Limited

InventorThomas C. Sparks

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Abstract

Network terminating terminal apparatus, for use in an Integrated Services Digital Network, comprises a U-interface and a S/T interface. The U-interface allows the integrated terminal apparatus to communicate with a central office directly, without a separate network terminator. Remote terminals may be connected to the network terminating terminal apparatus, via its S/T interface. The network terminating terminal apparatus then serves as a conventional network terminator. The network terminating terminal apparatus includes circuitry for controlling D-channel access by the integrated terminal apparatus. The circuitry detects the framing of the signal received at the U-interface and the D-channel information from the remote terminals and ensures that the D-channel data from the integrated terminal apparatus is supplied to the S/T interface at the appropriate time for insertion into the D-echo channel of the signal returned to the remote terminals. In addition, the D-channel data from the integrated terminal apparatus is supplied to the U interface, with the D-channel from remote terminals, for transmission in D-channel of the signal to the central office.

Claims12

Dependent claims

Network terminating terminal apparatus, for an Integrated Services Digital Network, comprising:

a U-interface (412) for connection to the network;
a U-transceiver (411) for transmitting signals to, and receiving signals from, the network via said U-interface serving to extract from signals received via said U-interface (412) B-channel data and D-channel data, a clock signal and framing signal;
an S/T interface for connecting to remote terminal apparatus and a S/T transceiver (414) for transmitting signals to, and receiving signals from, said remote terminal apparatus via said S/T interface (425);
a user interface and LAPD circuit (418) for interfacing local station apparatus (419, 422), including D-channel protocol means responsive to said user interface for generating a D-channel access signal (D.sub.request, D.sub.class) for securing access to said D-channel to enable said user interface and LAPD to transmit data to said U-transceiver (411);
D-channel monitoring and contention resolution means (427) for monitoring a D-channel in a data signal from said protocol means and signals received from said remote terminals by said S/T transceiver (414) and resolving contention between said user interface and LAPD (418) and said remote terminal apparatus and for providing to said user interface and LAPD 418 a signal (D.sub.grant) enabling access D.sub.grant and a D-channel control signal (D.sub.b);
D-channel access means responsive to said framing signal, said clock signal, said access enabling signal (D.sub.grant) and said D-channel control signal (D.sub.b) for controlling application to said U-transceiver 411 of B-channel data and D-channel data in said data signal from said user interface (TX.sub.LAPD) and LAPD circuit (418) selectively;
said D-channel access means (423) serving to supply a D-channel control bit (E.sub.in) to said S/T transceiver, said S/T transceiver being arranged to transmit said bit as an ECHO signal to said remote terminals.

4 more elements

Network terminating terminal apparatus, for an Integrated Services Digital Network, comprising:

a U-interface (412) for connection to the network;
a U-transceiver (411) for transmitting signals to, and receiving signals from, the network, said U-transceiver (411) serving to extract from signals received via said U-interface (412) B-channel data and D-channel data, a clock signal and framing signal, and TX to C/O;
an S/T interface for connecting to remote terminal apparatus and a S/T transceiver (414) for transmitting signals to, and receiving signals from, said remote terminal apparatus via said S/T interface (425);
a plurality of local terminal apparatus each comprising a user interface and LAPD circuit (418) for interfacing local station apparatus (419, 422), including D-channel protocol means responsive to said user interface for generating a D-channel access signal (D.sub.request, D.sub.class) for securing access to said D-channel to enable said user interface and LAPD to transmit data to said U-transceiver (411);
D-channel monitoring and contention resolution means (427) for monitoring a D-channel in a data signal from said protocol means and signals received from said remote terminals by said S/T transceiver (414) and resolving contention between said user interface and LAPD (418) and said remote terminal apparatus and for providing to said user interface and LAPD 418 a signal enabling access (D.sub.grant) and a D-channel control signal (D.sub.b);
and
D-channel access means responsive to said framing signal, said clock signal, said access enabling signal (D.sub.grant) and said D-channel control signal (D.sub.b) for controlling application to said U-transceiver 411 of B-channel data and D-channel data (TX.sub.LAPD) in said data signal from said user interface and LAPD circuit (418) selectively;
said D-channel access means (423) serving to supply a B-channel control bit to said S/T transceiver, said S/T transceiver being arranged to transmit said bit as an ECHO signal to said remote terminals;
wherein the respective D-channel inputs (D.sub.out) and outputs (E.sub.in) of the D-channel access means of said plurality of local terminal apparatus are connected in tandem between the D-channel input port (E.sub.in) and D-channel output port (D.sub.out) of said S/T transceiver.

6 more elements

Dependencies are inferred from the claim text.