Demand driven access mechanism

Claim 2

A demand driven access mechanism for enabling a station to seize use of a communication channel shared with one or more other stations, said mechanism comprising: first logic means responsive to a signal from said station for producing a station request signal if the station is either ready to seize use of the channel or is using the channel and for producing a station not-request signal if the station is neither ready to seize use of the channel nor is using the channel; second logic means for producing either an enable signal to said station or a not-enable signal, said second logic means being responsive to the station's enable signal and a request signal from a second station or to the stations's not-request signal and the stations's not-enable signal to produce said enable signal whenever the station is enabled by its respective second logic means and no request signal is present from the second station's first logic means or whenever the station's second logic means is not producing said enable signal and the station is ready to seize use of the channel.

Claim 3

Apparatus according to claim 1 wherein said second logic means further includes priority ordering means responsive to the request signal and selected not-enable signals of other stations to selectively provide said enable signal when two or more request signals are present from other stations.

Claim 4

Apparatus according to claim 2 wherein there are at least three stations sharing said channel and said priority ordering means does not provide said enable signal whenever (a) the respective stations is not enabled and the second station requests use of the channel, or (b) the respective station is not enabled and does not request use of the channel, or (c) the third station requests use of the channel and either the respective or the second station is enabled.

Claim 5

Apparatus according to claim 3 wherein there are at least four stations sharing said channel and said priority ordering means additionally does not provide said enable signal whenever (d) the fourth station requests use of the channel and none of the other stations is enabled.

Claim 6

Apparatus according to either of claims 3 or 4 wherein said enable signal is produced whenever the conditions for not producing the enable signal are not present.

Claim 7

Apparatus according to claim 1 wherein there are at least three stations sharing said channel and wherein said second logic means is additionally responsive to the request signal and not-enable signal from a third station, said second logic means producing said not-enable signal whenever (a) the enable signal is provided to the respective station and a request signal is provided from the second station, or (b) the not-enable and not-request signals are provided by the respective station, or (c) the request and not-enable signals are provided from the third station.

Claim 8

Apparatus according to claim 6 wherein there are at least four stations sharing said channels and wherein said second logic means is additionally responsive to the request signal and not-enable signals from a fourth station, said second logic means additionally producing said not-enable signal whenever (d) the request and not-enable signals are provided from the fourth station and the not-enable signal is provided from the third station.

Claim 9

Apparatus according to either of claims 6 or 7 wherein said enable signal is produced whenever said not-enable signal is not produced.

Claim 10

In a communication system having a plurality of stations each capable of seizing use of a communications channel shared by said stations, the improvement comprising, at each station, a demand driven access mechanism for enabling the respective station to seize use of the channel, said mechanism comprising: A. first logic means responsive to the respective station for producing a station request signal whenever the respective station is either ready to seize use of the channel or is using the channel, and for producing a station not-request signal whenever the respective station is neither ready to seize use of the channel nor using the channel; B. second logic means for producing either an enable signal or a not-enable signal, said second logic means comprising (i) first AND gate means responsive to the respective station's enable signal and to a request signal from a second station to produce a first logic signal, (ii) second AND gate means responsive to the respective station's not-request and not-enable signal to produce a second logic signal, (iii) OR gate means responsive to either said first or second logic signals to produce a third logic signal; (iv) enable means responsive to said third logic signal to produce said not-enable signal and responsive to the absence of said third logic signal to produce said enable signal; and C. output means for providing said enable signal to the respective station.

Claim 11

In a communication system having a plurality of stations each capable of seizing use of a communications channel shared by said stations, the improvement comprising, at each station, a demand driven access mechanism for enabling the respective station to seize use of the channel, said mechanism comprising: A. first logic means responsive to the respective station for producing a station request signal whenever the respective station is either ready to seize use of the channel or is using the channel, and for producing a station not-request signal whenever the respective station is neither ready to seize use of the channel nor using the channel; B. second logic means for producing either an enable signal or a not-enable signal, said second logic means comprising (i) first AND gate means responsive to the respective station's enable signal and to a request signal from a second station to produce a first logic signal, (ii) second AND gate means responsive to the respective station's not-request and not-enable signal to produce a second logic signal, (iii) OR gate means responsive to either said first or second logic signals to produce a third logic signal; (iv) enable means responsive to said third logic signal to produce said not-enable signal and responsive to the absence of said third logic signal to produce said enable signal; and C. output means for providing said enable signal to the respective station.

Claim 12

Apparatus according to claim 9 wherein said second logic means further includes third AND gate means responsive to the request signal and not-enable signal from a third station to produce a fourth logic signal, said OR gate means being responsive to any of said first, second or fourth logic signals to produce said third logic signal.

Claim 13

Apparatus according to claim 10 wherein said second logic means further includes fourth AND gate means responsive to the request signal and not-enable signal from a fourth station and said not-enable signal from said third station to produce a fifth logic signal, said OR gate means being responsive to any of said first, second, fourth or fifth logic signals to produce said third logic signal.

Claim 14

Apparatus according to any one of claims 9 through 11 wherein said enable means comprises inverter means responsive to said third logic signal to invert it, and flip-flop means responsive to the inverted third logic signal to produce said enable signal and responsive to the absence of said inverted third logic signal to produce said not-enable signal.