Communication networks

A method of configuring a network which includes a multiplicity of interconnected switch units and which incorporates a number of stations connected thereinto each via a switch unit, wherein

• each switch unit has a plurality of communication port pairs each comprising an OUT and an IN port, each of at least one unit having at least three such pairs;
• via their respective port pairs, each switch unit is connected to at least one other switch unit by a communication path, there being at least one path to each such other unit, each path comprising an OUT and an IN channel, each of at least one unit being so connected by at least three paths to other units;
• and
• for each switch unit its OUT and IN ports are internally interconnectable such that
• if there is not port pair that must be involved in this interconnection, and is thus a mandatory pair, then the OUT port of any pair can be connected to the IN port of any pair,
• while if there is such a mandatory port pair then the unit's port pairs are in a notional sequence with the mandatory pair at one end, and the OUT port of any non-mandatory pair can at least be connected either to the IN port of that pair or to the IN port of any of the port pairs sequentially nearer the mandatory pair, and the OUT port of the mandatory port pair can be connected to the IN port of any non-mandatory pair;
• whereby with the provisos above, the switch units are capable of being interconnected via their non-mandatory port pairs one with another in an entirely arbitrary arrangement, and regardless of the actual physical-disposition interconnection arrangement of the units relative one to another the network may be configured as a ring by suitably internally interconnecting each such unit's communication port pairs so as to form a circular communications link serially joining all of the units in the network;
• and
• wherein in operation there are employed both channels of each of the communication paths that are used in the configured network,
• in which method:
• one particular station being abitrarily designated the primary station, and being connected into the network by its own switch unit, it causes that unit to poll the unit's port pairs in sequence to see whether each is connected by a communication path to another device and if any such device replies then that device is connected into the network along that communication path and subsequently caused similarly to poll its own port pairs, if any, in sequence, this occurring before the preceding device polls its sequentially next port pair, and so on until all the repeater units and stations and the communication paths therebetween have been tested, found either acceptable, faulty or absent, and if the first linked into the network so as electrically to connect the devices and the communication paths therebetween into a closed ring.

Switch units suitable for use in a communications network which includes a multiplicity of interconnected switch units, wherein;

• each switch unit has a plurality of communication port pairs each comprising an OUT and an IN port, each of at least one unit having at least three such pairs;
• via their respective port pairs, each switch unit is connected to at least one other switch unit by a communication path, there being at least one path to each such other unit, each path comprising an OUT and an IN channel, each of at least one unit being so connected by at least three paths to other units;
• and
• for each switch unit its OUT and IN ports are internally interconnectable such that
• if there is not port pair that must be involved in this interconnection, and is thus a mandatory pair, then the OUT port of any pair can be connected to the IN port of any pair,
• while if there is such a mandatory port pair then the unit's port pairs are in a notional sequence with the mandatory pair at one end, and the OUT port of any non-mandatory pair can at least be connected either to the IN port of that pair or to the IN port of any of the port pairs sequentially nearer the mandatory pair, and the OUT port of the mandatory port pair can be connected to the IN port of any non-mandatory pair;
• whereby with the provisos above, the switch units are capable of being interconnected via their non-mandatory port pairs one with another in an entirely arbitrary arrangement, and regardless of the actual physical-disposition interconnection arrangement of the units relative one to another the network may be configured as a ring by suitably internally interconnecting each such unit's communication port pairs so as to form a circular communications link serially joining all of the units in the network;
• wherein in operation there are employed both channels of each of the communication paths that are used in the configured network, and
• wherein in operation there are employed both channels of each of the communication paths that are used in the configured network, and
• wherein each switch unit has four communications IN/OUT port pairs, one of which is mandatory, which unit includes
• (a) switching means associated with each IN/OUT port pair, each of which switching means may be regarded as being notionally a multiway switch having a wiper blade connected to a centre contact and moveable into engagement with any one of a multiplicity of outer contacts so as to connect the centre contact thereto, the centre contact being connected to the OUT port of the port pair and the outer contacts being connected, one each, to the IN port of the same port pair and to the IN ports of the relevant other port pairs, with the proviso that the connections to the IN port of the mandatory port pair are made via a common switching means allowing the connections to be made instead to the OUT port of the mandatory port pair, whereby by appropriately setting the switching means the OUT port of any port pair may be connected through the wiper blade to the IN port of any relevant port pair;
• (b) control means for determining for each switching means with which of the outer contacts the wiper is to be engaged, and thus to which of the IN ports the switching means' centre contact is to be connected, and for determining for the mandatory port pair bypass switching means whether the connections to its IN ports are made instead to the OUT port;
• and
• (c) signal detect means associated with the IN port of each non-mandatory port pair and providing data to the control means in dependence upon which is in part made the determination of which contacts are to be connected.

A communications network, comprising:

• a plurality of switch units, each having a plurality of first port pairs, each first port pair having an IN port and an OUT port, each switch unit additionally having interconnection means for selectively connecting the OUT ports of the first port pairs to the IN ports of the first port pairs in a predetermined pattern;
• a station;
• a further switch unit having a plurality of first port pairs and a second port pair that is connectable to the station, each of the first and second port pairs having an IN port and an OUT port, the further switch unit additionally having interconnection means for selectively connecting the OUT port of the first and second port pairs to the IN ports of the first port pairs and to an intermediate connection point associated with the second port pair in a predetermined pattern, and bypass means for connecting the intermediate connection point to the IN port of the second port pair when the station is connected to the second port pair and for connecting the intermediate connection point to the OUT port of the second port pair when the station is disconnected from the second port pair;
• and
• means for interconnecting the first port pairs of the switch units so that each switch unit is connected to at least one other switch unit by a communication path, each path including an OUT channel and an IN channel,
• wherein the first port pairs of the switch units are selectively connected by their respective interconnection means to configure the network as a ring network which serially links all of the switch units, and wherein both channels of all communication paths that are used in the configured network are employed to convey information.