Telefonaktiebolaget Lm Ericsson (publ)

Tomas A Eriksson

Per A Ljungberg

Hao Jiang

Lars E Hammarberg

Rolf S Sandin

An overvoltage protector circuit for telecommunication equipments is disclosed. The protector circuit includes a gas discharge tube connected to a communication line for passing any harmful surge currents appearing in the line to ground. A degradation detector circuit is arranged to detect any degradation of the gas discharge tube, the detector circuit comprises a reference gas discharge tube with a higher breakdown voltage than the supervised gas discharge tube and an alarm circuit loop connected to an alarm system. The alarm system is arranged to detect when current is breaking through the reference gas discharge tube and to initiate a degradation alarm.

Overvoltage protector circuit and a detector circuit for supervising such a protector circuit

In a packet switch, which is intended for packets of constant length, and which, between switch ports, is divided into a number of nodes (12) and transmission links (14), where the nodes carry out space selection and the transmission links offer point-to-point transmission between the nodes, link grouping is carded out. More particularly, from multiple parallel physical links coming in the switch, link groups are produced, each in the form of a logical link with a bandwidth that is the sum of the bandwidths of the physical links included in the link group, said logical link being restored to outgoing parallel physical links from the switch. One or more link protocols (G1,G2) are used according to which a label in the packet's header is made to describe a route that holds together the grouped links through the entire switch, such that bits in the label describing the route over a certain transmission link are the same for packets belonging to the same link group.

Method to provide link grouping in a packet switch

The present invention relates to a method and to an arrangement for regenerating timing pulses from an information-carrying pulse train of the NRZ-type. The method can be used in a telecommunication system to create a timing signal which is synchronous with the information-carrying pulse train, so as to enable the pulses of the generated timing signal to be used as clock pulses when reading information from the original pulse train. The information-carrying pulse train is differentiated and rectified in a known manner, wherein the rectified pulse train signal will contain solely positive or solely negative pulses originating from level shifts of the pulse train signal. A commutating filter is given a resonance frequency which corresponds to the frequency of the NRZ-signal, and the rectified pulse train signal is supplied to the commutating filter, which generates timing pulses during those periods in which no pulses occur in the rectified pulse train signal. The commutating filter produces a timing signal which contains one pulse for each bit in the original information-carrying pulse train.

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Stockholm, Sweden

Tomas A Eriksson