Nortel Networks Corporation

Standard Telephones & Cables Limited

Michael Philip Dyer

Peter John Dyke

Duncan John Forbes

Anthony W Sweet

Mark James Parry

Peter John Etter

A communications network having two complementary optical networks each connectable to a headend, each optical network comprising a plurality of periodic interleaving filters serially connected by optical waveguides such that an output port of one periodic interleaving filter is couple to an input port of another periodic interleaving filter, and wherein an input or output node of the network is formed by a non-serially connected input or output port of a periodic interleaving filter.

Optical network architecture

A system () to enable the transfer of Internet protocol (IP) format data () over a point-to-multipoint passive optical network (PON,) is illustrated in FIG.. An exchange () is connected to a plurality of outstations () via an optical communication resource () including a passive optical splitter () providing isolation to individual outstations. Media access control of the plurality of outstations is administered by the exchange (), with collision detection logic () in the exchange determining collision () of Internet protocol (IP) encoded data communicated thereto through the PON (). The IP encoded data realises a transport mechanism through the PON. Each of the plurality of outstations () and the exchange () is adapted to pass data in an IP format to and from the optical communication resource such that IP encoded data is transported, in use, directly between the outstation and the exchange.

System and method for transfer of IP data in an optical communication networks

Optical fibre ducting system

A local telecommunications network system IS arranged to provide a first asymmetric digital subscriber line (ADSL) service in a first frequency band to a first set of subscribers and a second very high bit rate digital subscriber line (VDSL) service in a second frequency band higher than the first frequency band to a second set of subscribers. Interference between the two types of digital traffic within the multi-pair feeder cables leading to the exchange is suppressed by low pass filtering the ADSL traffic and high pass filtering the VDSL traffic. The filtering may be applied to the line cards to which each subscriber line is connected.

Providing digital services to telephone subscribers

A passive optical network having a plurality of optical splitters/combiners each comprising first and second through ports and at least one drop port. The through ports of the plurality of splitters/combiners are concatenated to form a linear arrangement having two end through ports. Optical signals may be transmitted between the end through ports by means of the linear arrangement; and signals may be transmitted between at least one of the end through ports and one of the drop ports by means of the linear arrangement. The splitter/combiners can be inserted to form drop points in a ring or dual-homed passive optical network to provide flexibility in provision of protection and network reconfiguration.

Passive optical network arrangement

The direct current line feed for a telephone subscriber's line is derived from a variable voltage source connected to the line. In one case, the source is series connected in one leg of the line while in the other case it is connected across the line. In the first case there is a constant current source across the line while in the second case the voltage source is a constant current device. In both cases a pair of matching resistors is connected across the line with the center tap grounded to provide a high resistance balanced termination for the line. In both cases a high impedance monitor is connected across the line to monitor the voltage conditions on the line, and this, via a control circuit controls the voltage source and the separate constant current device if provided. This enables line voltage to be adjusted to take account of line length without introducing undesirably large dissipation.

Growing community of inventors

Stansted, United Kingdom

Michael Philip Dyer