US 4,787,081 AGranted

Time division multiplex equipment for use in data transmission equipment

AssigneeStc PLC

InventorsDerek B. Waters, Michael J. Sexton

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Abstract

A data transmission equipment, known as a primary digital multiplex (PDMX) consists of a bus structure formed by parallel lines on a printed circuit board, with the circuit units (1,2,3,4,5) on printed circuit cards set at right angles to the bus structure. The circuit units include a control unit (1,2) also called a core facilities unit, which acts as an interface to one or more 2Mb/sec. trunks, and so-called tributary units (3,4,5) which give access to subscriber and other outlets. Various networks using one or more such PDMX equipment are described. The signalling and control arrangements for the equipment use a signalling processing unit (2) and a tone processor (6). The signalling processing unit monitors the bus for signals and line conditions and issues signals appropriately. The tone processor functions in a generally similar manner. Note that PDMX is one of STC PLC Trade Marks.

Claims15

Dependent claims

Data transmission equipment, which includes a control unit which exercises overall control of the operations of the equipment and one or more tributary units, said units being interconnected by respective bus conductors of a common bus structure to which all of said units are connected, all transmissions over the bus structure being digital, wherein:

(a) a high bit-rate incoming and outgoing digital trunk is coupled to the control unit when the equipment is in use;
(b) said tributary units each provide interfaces for one of more digital highways of lower or equal bit rate than that of said high bit rate trunk, or for one or more analogue channels, which said highways include one or more highways to subscriber stations;
(c) the control unit controls the establishment, maintenance and breakdown of connections between the high bit rate trunk and said digital highways and analogue channels, such that the control unit is involved in the establishment of all connections set up through the equipment;
(d) the respective bus conductors which interconnect the control unit and the tributary units are allocated time slots for connections between the said high bit-rate trunk and respective ones of said highways or channels, wherein such a connection can be allocated one or more of said time slots dependant on the bandwidth required, which allocation is effected under the control of the control unit;
(e) connections between the control unit and such of the tributary units as are present being effected by messages sent over the bus structure, each of which messages is addressed with the address of the unit for which that message is destined, and is sent at a time slot allocated to the bus structure for the connection to which it relates;
(f) the address of a said tributary unit is responded to by address responsive means in that tributary and relates to that unit as such and not to its location in the equipment, whereby a said tributary unit can be located anywhere in the equipment without alteration of its address;
(g) said tributary units can handle different customer services, which may require different bandwidths;
and
(h) the control unit includes memory means in which details of the current allotments of time slots and bus conductors to the customer services of all of the tributary units are stored.

6 more elements

Data transmission equipment for handling data in digital form in time division multiplex manner, which includes a control unit which includes connection processing means which exercises overall control of the operations of the equipment, one or more tributary units, at least one additional processing unit which serves all of said tributary units, said additional processing unit being physically separate from the control unit and the tributary units, and a common bus structure to which all of said units are connected, all transmissions over the bus structure being digital, wherein:

(a) the control unit also controls an interface for at least one high bit-rate incoming/outgoing trunk coupled to the control unit, while each said tributary unit acts an an interface to one or more other data highways, which other highways may include lower bit-rate highways giving access to subscriber stations or analogue channels;
(b) the control unit controls the establishment, maintenance and breakdown of connections between the high bit-rate trunk and said digital highways and analogue channels;
(c) a said additional processing unit handles data appropriate to the connections in the process of establishment, or already established, via the equipment, which data is additional to the intelligence content of said connections;
(d) a said additional processing unit effects said data handling by monitoring the bus structure to ascertain the data or other information thereon relating to the connection;
(e) a said additional processing unit responds to the results of its said monitoring of the bus structure to generate further data or other information which is applied to the bus structure in a manner appropriate to the connection to which it relates;
and
(f) a said additional processing unit effects said monitoring and generation separate from the operations of the control unit and under the control of its own software.

4 more elements

Dependencies are inferred from the claim text.