Abstract: Enhanced availability and survivability of communications between geographically remote locations with a minimum of redundancy of transmission facilities and media is provided by a survivable bus network capable of providing continued interprocessor or other communications in the event of multiple bus outages. It consists of multiple busses, bus isolation device (BIDs) and two types of network interface processors (NIPs). The BIDs electrically isolate bus segments on either side of a connection so that if a fault occurs only the segment containing the fault will be affected. The first type of NIP connects to one bus and performs the usual function of providing an electrical and software interface between the network and one or more subscriber processors. The second type is a bridge which performs these same functions but connects to two busses and has the capability to transfer traffic as it appears on either bus to the other.

Abstract: A device and technique for providing stability to a coherent delay line clock. A voltage controllable delay is combined with the lumped delay line of a coherent delay line clock to enable the control of the period of the clock. The voltage controllable delay is obtained by comparing the clock count during a predetermined time period against a fixed number N to obtain a difference count. The difference count is then integrated to form a bias voltage for control of the additional delay. The delay line period will then be a ratio of the predetermined period to the fixed number N, which number may be digitally modified to provide a source of variable frequency.