Priority counter

Claim 1

A device for determining priority among request signals occurring at arbitrary instants on request line terminals of a plurality of outer stations, comprising: an interrogation unit including a succession of switching stages and a clock pulse generator for successively driving the positions of all said stages, during a predetermined period; blocking means including gating means coupled between said stages and said terminals to stop the driving of said stages in response to the occurrence of a first request signal on said terminals and produce a treatment signal for the station at which said first request signal has occurred, and delay means activated by said request signal for blocking the generation of the treatment signal for a waiting time interval exceeding the time between the instant of the stopping of said stages and the end of said predetermined period characterized in that an auxiliary unit is provided, which comprises at least two switching positions and an additional switching positions, means controlled by the clock pulse generator for driving the said auxiliary unit through its positions, with the exception of said additional position, means for switching said auxiliary unit through to said additional position under the combined control of a request signal on an interrogated request line terminal and a clock pulse, means for generating a wait signal under the control of at least one of said two positions, and means for generating said treatment signal under the control of said additional position.

Claim 2

A device for determining priority among request signals occurring at arbitrary instants on request line terminals of a plurality of outer stations, comprising: an interrogation unit including a succession of switching stages and a clock pulse generator for successively driving the positions of all said stages, during a predetermined period; blocking means including gating means coupled between said stages and said terminals to stop the driving of said stages in response to the occurrence of a first request signal on said terminals and produce a treatment signal for the station at which said first request signal has occurred, and delay means activated by said request signal for blocking the generation of the treatment signal for a waiting time interval exceeding the time between the instant of the stopping of said stages and the end of said predetermined period characterized in that an auxiliary unit is provided, which comprises at least two switching positions and an additional switching positions, means controlled by the clock pulse generator for driving the said auxiliary unit through its positions, with the exception of said additional position, means for switching said auxiliary unit through to said additional position under the combined control of a request signal on an interrogated request line terminal and a clock pulse, means for generating a wait signal under the control of at least one of said two positions, and means for generating said treatment signal under the control of said additional position.

Claim 5

A device for determining priority among request signals occurring at arbitrary instants on request line terminals of a plurality of outer stations, comprising: an interrogation unit including a succession of switching stages and a clock pulse generator for successively driving the positions of said stages for a predetermined period; blocking means including gating means coupled between said stages and said terminals to stop the driving of said stages in response to the occurrence of a first request signal on said terminals and produce a treatment signal for the station at which said first request signal has occurred, and delay means for blocking the generation of the treatment signal for a time interval exceeding the time between the instant of the stopping of said stages and the end of said predetermined period said gating means including a first set of NAND gates each having a first input connected to an assigned terminal, a second input connected to said clock pulse generator, a third input connected to the output of an assigned stage, and an output connected to the input of said stage; a second set of NAND gates each having an input connected to an assigned switching stage, a second input connected to the output of said delay means and an output for producing a treatment signal and, alternatively a wait signal for a station; and an additional NAND gate having inputs connected to said terminals and an output connected to the input of said delay means.

Claim 6

A device for determining priority among request signals occurring at arbitrary instants on request line terminals of a plurality of outer stations, comprising: an interrogation unit including a succession of switching stages and a clock pulse generator for successively driving the positions of said stages for a predetermined period; blocking means including gating means coupled between said stages and said terminals to stop the driving of said stages in response to the occurrence of a first request signal on said terminals and produce a treatment signal for the station at which said first request signal has occurred, and delay means for blocking the generation of the treatment signal for a time interval exceeding the time between the instant of the stopping of said stages and the end of said predetermined period said gating means including a first set of NAND gates each having a first input connected to an assigned terminal, a second input connected to said clock pulse generator, a third input connected to the output of an assigned stage, and an output connected to the input of said stage; a second set of NAND gates each having an input connected to an assigned switching stage, a second input connected to the output of said delay means and an output for producing a treatment signal and, alternatively a wait signal for a station; and an additional NAND gate having inputs connected to said terminals and an output connected to the input of said delay means.