International Business Machines Corporation

Other

Heinz J Keller

Johann R Mueller

Erwin A Zurfluh

Ernst H Rothauser

Urs H Bapst

Heinrich Meyr

Hans R Muller

A ring communication system comprises distribution panels (13) for inserting extension lines (15) and attached stations (19) into the communication ring (11); insertion is requested and controlled by DC signaling from the station via a phantom path. To allow attachment of several stations via additional extension lines (25) to a single basic extension line (15), extension distribution panels (23) are provided comprising line insertion modules (31) like the basic distribution panels. Insertion of a station and its additional extension line (25) up to the EXP is still controlled by DC signaling from the station, but insertion of the basic extension line (15) is controlled by a tone signal transferred from the EXP to the basic distribution panel via a phantom path. The EXP (23) needs no own power supply because DC power is provided from the basic distribution panel (13) via the phantom circuit of the basic extension line.

Extension arrangement and station connecting method for a ring

In a communication system providing multiple access to transmission facilities for a plurality of stations (17, 21), two separate networks (11, 13) are provided: One is a token ring (11) on which access tokens and data are transmitted, the other is a high-speed optical fiber transmission ring (13) on which only large-volume data blocks are transmitted between particular stations (21) which are attached to both rings, but no access information. A token manager (27) in the token ring (11) provides at regular intervals particular tokens that are only used by the particular stations (21) for obtaining access to the high-speed ring (13), but also provides other tokens for regulating access to the token ring (11) for other stations (17). Special access nodes (23) are provided which allow to connect the particular stations (21) to the high-speed ring (13) without extending its length.

Communication system comprising overlayed multiple-access transmission

In a ring communication system comprising selectively connectable data stations, each station has connecting circuitry including a phase-locked loop arrangement (111) which is frozen at its current frequency and phase in response to a signal interruption caused by a station insertion or removal operation. Control logic (113) generates a freeze control signal in dependence of the signal energy status on input lines (75). This control signal activates gates (149, 151) and switches (155, 157) to interrupt change control signals of the phase-locked loop circuitry and to keep an oscillator control voltage at a given value. The control logic also provides an auxiliary data signal during the freeze interval which is applied to the ring to keep stations downstream in synchronism. By this method and arrangement, undesired reactions and excursions of the phase-locked loop circuitry in response to a signal energy outage are prevented, and synchronization can be rapidly regained after station insertion or removal.

Method for connecting or disconnecting selected stations in a ring

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Ruschlikon, Switzerland

Heinz J Keller