US 4,181,909 AGranted

Method and appratus for initializing remote data communication equipment

AssigneeSperry Rand Corporation

InventorsSamuel C. Pyeatte, Michael M. Austin

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Abstract

Apparatus associated with a remote communication station responds to predetermined sequences of characters received over a communication channel by initializing or conditioning equipment located at the remote station. The predetermined sequences include a plurality of synchronization characters followed by a plurality of identification characters, the latter of which identify the nature of the initialization or conditioning to occur at the remote station. The apparatus "looks" bit by bit at received data to determine when a synchronization character is received. When such a character is detected, the apparatus "looks" at the succeeding characters on a character by character basis to ascertain whether the predetermined sequence of characters is received. For each character received, a programmable read only memory produces an output which is compared with reference signals produced by another programmable read only memory. If a mismatch occurs, the apparatus is reset to again "look" at the received data on a bit by bit basis. If matches occur for the remaining characters of the sequence, then the apparatus signals the remote station equipment to initialize or condition the equipment in accordance with the identification characters received.

Claims16

Dependent claims

In a data communications system having one or more host stations, one or more remote stations, and means interconnecting said stations, said host station including means for transmitting predetermined sequences of data characters over said interconnecting means to said remote station, and said remote station including data processing equipment, data storage units, and loading apparatus responsive to initialization signals for applying data to the data processing equipment from a data storage unit identified by said initialization signals, apparatus for initializing said remote station comprising

means coupled to said interconnecting means for receiving and temporarily storing data transmitted by said host station,
means coupled to said receiving and storing means for detecting receipt of said predetermined sequences of data characters, said detecting means comprising
means for producing first reference signals in response to received data characters,
resettable means for producing second reference signals,
means for producing a sync signal in response to certain reference signals being produced by said first reference signal producing means,
resettable synchronization means responsive to said sync signal for thereafter producing a comparator signal and a character clock signal each time a certain number of data bits are received from the host station,
comparing means responsive to said comparator signal for comparing said first reference signals with said second reference signals, and for producing a match signal if the compared signals match and a mismatch signal if the compared signals do not match,
means for producing a reset signal to reset said second reference signal producing means and said synchronization means in response to production of a mismatch signal, and
means for producing initialization signals if at least a certain number of data characters are received and match signals only are produced, and for applying said initialization signals to said loading apparatus, the value of said initialization signals depending upon the predetermined sequence received.

6 more elements

Apparatus for detecting a predetermined sequence of data characters transmitted over a transmission channel, said sequence including a plurality of synchronization characters followed by a plurality of identification characters, each character being composed of a plurality of data bits, said apparatus comprising

means for receiving and storing data bits transmitted over said transmission channel,
means for producing a sync signal when a particular sequence of bits is received,
synchronization means responsive to said sync signal for thereafter producing a comparator signal each time a data character is received, said synchronization means comprising
means coupled to said receiving and storing means for producing first reference signals in response to received data characters, the code value of said first reference signals being dependent upon the data characters received, and
logic means for producing said sync signal in response to certain first reference signals being produced,
means responsive to said comparator signals for comparing second reference signals with said first reference signals, and
means for producing an initialization signal if a predetermined number of synchronization characters or more are received followed by a predetermined number of identification characters, and if the compared signals match.

4 more elements

Dependencies are inferred from the claim text.