A protocol system for data processing equipment, particularly equipment used in building automation monitoring and control systems for air-conditioning control and monitoring of fire and security points is disclosed having a plurality of stations connected to a data bus, each station having an apparatus for monitoring the traffic on the data bus, calculating its turn to transmit or time slot during which it is permitted to transmit data on the bus and updating its calculated turn or time slot af…

A local area network control apparatus is interposed between a host computer whose main storage stores an appropriate number of user programs and a plurality of interactive termials which have protocols of any desired level. The apparatus comprises a program module which has a predetermined bypass function, a program module which has a function of executing a specified protocol, and a control table in which names of the user programs to be handled, designations of the interacting terminals there…

A communication adapter circuit (10) is connected to a processor through processor I/O interface buses (12, 14). Data and control signals are provided through the buses (12, 14) to a timer circuit (18), a programmable peripheral interface circuit (20), an asynchronous and bisynchronous control circuit (22) and an SDLC/HDLC control circuit (24). Each of the control circuits (22, 24) includes parallel-to-serial and serial-to-parallel conversion circuitry. A clock select circuit (32) operates in co…

Secondary storage subsystems exchange messages and data with host data processing systems and also forward messages between host systems. Host systems thereby communicate with each other in addition to having access to data in subsystem storage. Access to subsystem storage is initiated by a “request” sent from a host to the subsystem. Each request is a message containing an array of one or more commands, each command specifying a transfer of data or a control function to be performed by the subs…

A distributed data processing system including a general, passive, communications network, and a plurality of local systems which each have a central processing unit, associated memory, and at least one peripheral device. The control of the intercommunication is effected by respective system intercommunication processors, each interfacing one local system to the network. Each systems intercommunications processor is attached to the network by means of a respective communication module. A communi…

Network interface software for use in a network of computers includes software providing protocols for transmission of messages without high level software acknowledgments required. Negative acknowledgments are relied on to indicate the failure of complete message reception.

A battery powered receiver including a adaptive signal decoder is disclosed which is capable of processing detected encoded signals in accordance with a plurality of decoding schemes. The decoder has an equivalent microcomputer implementation. Energy conservation means operating independently of the detected signals acts to conserve the energy of the battery.

The bit streams, transporting the frames, received from lines (6) are placed in register 12 in such a way that n bits are processed in parallel during a time interval T. Parallel processor 10 counts the consecutive logical “1” bits beginning at the low order (left most) bit of the n bits received in interval T and from the bits received in the previous interval T-1, to determine when this number is found equal to 5 which bits have to be deleted, and when this number is found equal to 6 whether a…

In a computer network system comprising a plurality of computers connected to a communication line, each computer executes a program including a function. In one of the computers, a judging section is supplied with a request indicative of the function from the program and judges whether or not the function can be executed by the above-mentioned one to produce a non-executable signal when the function cannot be executed by the above-mentioned one. Responsive to the non-executable signal, a reques…

The process disclosed is appliable to transmission of data of the multiplexed series type between entities capable of emitting or receiving data, to or from the line. Each entity connected to the line can access all the data flowing in the line, and all the exchanged data are modeled by a distributed data base which is updated and maintianed by the fact that each entity stores and updates a local copy of the corresponding useful part of the data base it contains. Each time an entity is placed in…