Data communication system

Claim 2

A data communication system for communicating with a plurality of stations at least one of which is remote from a central processor by a transmission link of significant communications delay, said system comprising: a central processor including a data scanner coupled to a system transmission line; one or more local stations each coupled to said system transmission line for time-shared communication with said central processor; a remote data scanner coupled to said central processor data scanner said central processor data scanner including means for providing time-shared communication with said remote data scanner; one or more transmission links of significant and fixed communications delay each having one end thereof coupled to said remote data scanner; said remote data scanner having means for compensating for the delay of said one or more transmission links to permit sequential communication by said central processor with said one or more local stations and, through said remote data scanner, with said remote stations on a time-shared basis; one or more transponders each coupled to a respective one of said transmission links at an end thereof opposite to said remote data scanner; and one or more remote stations coupled to each of said transponders.

Claim 3

The data communication system according to claim 1 wherein said remote data scanner includes for each one of said transmission links: first and second shift registers coupled to said central processor data scanner; modem means coupled to said first and second shift registers and also coupled to said one or more transmission links; said first shift register being operative to receive high speed serial data from said central processor data scanner and to transmit low speed serial data to said modem means; said second shift register being operative to receive low speed serial data from said modem means and to transmit high speed serial data to said central processor data scanner.

Claim 4

The data communication system according to claim 2 wherein each of said modem means includes a transmitting and a receiving channel adapted for coupling to respective paths of a respective one of said transmission links.

Claim 5

The data communication system according to claim 1 wherein each of said transponders comprise: modem means coupled to one of said transmission links; first and second shift registers each coupled to said modem means and each adapted for coupling to said one or more remote stations; said first shift register being operative to receive low speed serial data from said modem means and to convey high speed serial data to said remote stations; said second shift register being operative to receive high speed serial data from remote stations and to convey low speed serial data to said modem means.

Claim 6

The data communication system according to claim 1 wherein said remote data scanner includes: a plurality of modems each coupled to a respective one of said transmission links; a plurality of pairs of shift registers each pair being coupled to a respective one of said modems; means for applying high speed data from said central processor data scanner to one of each of said pairs of shift registers; means for applying low speed data from the other one of said pairs of shift registers to said central processor data scanner; and decoding means coupled to said plurality of shift registers and operative to selectively enable respective ones thereof to permit transfer of data from the selected shift register.

Claim 7

The data communication system according to claim 5 including timing means for determining the time intervals in which each of said shift registers is selected by said decoding meAns.

Claim 8

The data communication system according to claim 5 including means for monitoring data in each of said shift registers and on each of said transmission links.

Claim 9

The data communication system according to claim 1 wherein each of said transponders includes: means for detecting sync information received from said remote data scanner; and means for inhibiting transponder operation in the absence of sync detection.

Claim 10

The data communication system according to claim 1 wherein each of said transponders includes: clock means; means for synchronizing received data with clock pulses from said clock means; means for adjusting the timing of said clock means in response to the transition time of received data to synchronize said clock means with the timing of said data scanner.

Claim 11

A data communication system for communicating with a plurality of stations at least one of which is remote from a central processor by a transmission link of significant communications delay, said system comprising: a system transmission line having an insignificant communications delay; a central processor including a data scanner coupled to said system transmission line and operative to apply data thereto and receive data therefrom; one or more local stations, each coupled to said system transmission line for time-shared communication with said central processor; a remote data scanner coupled to said central processor data scanner; said central processor data scanner including means for providing time-shared communication with said remote data scanner; one or more transmission links of significant and fixed communications delay, each having one end thereof coupled to said remote data scanner; said remote data scanner having means for compensating for the delay of said one or more transmission links to permit sequential communication by said central processor with said one or more local stations and, through said remote data scanner, with said remote stations on a time-shared basis; one or more transponders, each coupled to a respective one of said transmission links at an end thereof opposite to said remote data scanner; one or more remote stations coupled to each of said transponders; said remote data scanner including: a plurality of data transmission means each coupled to a respective one of said transmission links and including means for receiving high speed serial data from said central processor data scanner and transmitting low speed serial data to said one or more remote stations, and further including means for receiving low speed serial data from said remote stations and transmitting high speed serial data to said central processor data scanner; and means coupled to said plurality of data transmission means and for selectively enabling respective ones thereof during predetermined time intervals of said central processor data scanner to permit transfer of data through a selected one of said transmission means between said central processor data scanner and a corresponding remote station.

Claim 12

A data communication system for communicating with a plurality of stations at least one of which is remote from a central processor by a transmission link of significant communications delay, said system comprising: a system transmission line having an insignificant communications delay; a central processor including a data scanner coupled to said system transmission line and operative to apply data thereto and receive data therefrom; one or more local stations, each coupled to said system transmission line for time-shared communication with said central processor; a remote data scanner coupled to said central processor data scanner; said central processor data scanner including means for providing time-shared communication with said remote data scanner; one or more transmission links of significant and fixed communications delay, each having one end thereof coupled to said remote data scanner; said remote data scanner having means for compensating for the delay of said one or more transmission links to permit sequential communication by said central processor with said one or more local stations and, through said remote data scanner, with said remote stations on a time-shared basis; one or more transponders, each coupled to a respective one of said transmission links at an end thereof opposite to said remote data scanner; one or more remote stations coupled to each of said transponders; said remote data scanner including: a plurality of data transmission means each coupled to a respective one of said transmission links and including means for receiving high speed serial data from said central processor data scanner and transmitting low speed serial data to said one or more remote stations, and further including means for receiving low speed serial data from said remote stations and transmitting high speed serial data to said central processor data scanner; and means coupled to said plurality of data transmission means and for selectively enabling respective ones thereof during predetermined time intervals of said central processor data scanner to permit transfer of data through a selected one of said transmission means between said central processor data scanner and a corresponding remote station.

Claim 13

The data communication system according to claim 10 wherein said central processor includes means for providing a time interval for each of said one or more local stations and remote stations during which said local station is communicative with said central processor.

Claim 14

The data communication system according to claim 10 wherein said central processor includes means for defining a data cycle having a series of successive frames of data followed by an interval containing sync information; and wherein said remote data scanner includes means for causing sequential transmission of a like frame of each data cycle on respective ones of said transmission links.

Claim 15

The data communication system according to claim 10 wherein said central processor includes: means for providing a time interval for each of said one or more local stations during which each local station is communicative with saId central processor; means for providing first and second time intervals for each of said remote stations during which each remote station can respectively transmit data to and receive data from said central processor.