Switching data set

Claim 2

In a data processing system, a remote switching data set for controlling the transmission of data between a central processor and either one of two different remote terminal units, said remote switching data set comprising: means in the central processor for generating an electrical signal at either one of two voltage levels, said signal having a predetermined period of time, modulating means operatively coupled to said aforementioned means for transforming said signal into a modulated signal, a communication channel adapted for transmitting said modulated signal, demodulation means for demodulating said modulated signal to one of the two voltage levels, first timing means responsive to said one voltage level for generating a first signal a predetermined time after the receipt of said voltage level, second timing means responsive to said one voltage level for generating a second signal a predetermined time after the receipt of said voltage level, and selection means responsive to said first signal for selecting one of the remote terminal units and responsive to said second signal for selecting the other of the remote terminal units, said selected remote terminal unit being operatively coupled to said demodulation means through said selection means.

Claim 3

A remote switching data set according to claim 1 wherein said first and second timing means are first and second monostable multivibrators respectively and wherein the unstable state of said second multivibrator is of longer duration than the unstable state of said first multivibrator.

Claim 4

A switching data set for selection one of a plurality of data transmission channels, said switching data set comprising: means for receiving an electrical signal from a communication channel, said signal having a first modulated signal representing a mark data signal and having a second modulated signal representing a space data signal, demodulating means responsive to said first modulated signal for generating a first direct current voltage level and responsive to said second modulated signal for generating a second direct current or voltage level, first timing means responsive to the transition from the first to the second direct current voltage level for generating a third signal a predetermined time after receipt of the transition and coincidence with said second direct current voltage level, second timing means responsive to the transition from the first to the second direct current voltage level for generating a fourth signal a predetermined time after receipt of the transition and coincidence with said second direct current voltage level, and channel selection means responsive to said third signal for selecting one of the data transmission channels and responsive to said fourth signal for selecting the other of the data transmission channels, said channel selection means operatively coupling the selected data transmission channel to said modulating means.

Claim 5

A switching data set for selection one of a plurality of data transmission channels, said switching data set comprising: means for receiving an electrical signal from a communication channel, said signal having a first modulated signal representing a mark data signal and having a second modulated signal representing a space data signal, demodulating means responsive to said first modulated signal for generating a first direct current voltage level and responsive to said second modulated signal for generating a second direct current or voltage level, first timing means responsive to the transition from the first to the second direct current voltage level for generating a third signal a predetermined time after receipt of the transition and coincidence with said second direct current voltage level, second timing means responsive to the transition from the first to the second direct current voltage level for generating a fourth signal a predetermined time after receipt of the transition and coincidence with said second direct current voltage level, and channel selection means responsive to said third signal for selecting one of the data transmission channels and responsive to said fourth signal for selecting the other of the data transmission channels, said channel selection means operatively coupling the selected data transmission channel to said modulating means.

Claim 6

A switching data set according to claim 3 wherein said first and second timing means are monostable multivibrators respectively.

Claim 7

A switching data set according to claim 4 wherein said fourth signal generated by said second multivibrator occurs a period of time after said third signal generated by said first multivibrator and the generation of said fourth signal negates the channel selection of said third signal.

Claim 8

A switching data set according to claim 4 wherein the timing period of the unstable state of both of said multivibrators is of a longer time duration than the longest space data signal during data transmission.

Claim 9

In a data processing system having a central processing unit operatively connected online to a command data set at one end of a telephone network and through a switching data set at the other end of the telephone network to either one of two different remote terminal unit channels, the command data set comprising: oscillation means generating a series of pulses at either one of two different pulse frequencies, modulation means operatively coupled to said oscillation means for modulating data information over said telephone lines, channel selection means responsive to command signals from the central processing unit for selecting one or the other of the remote terminal unit channels and operable for generating a channel selection control signal in response to said selection, and a timer responsive to said channel selection control signal and said oscillation means and operable for providing a first electrical signal of a first predetermined time period to said modulation means for selecting one of the remote terminal unit channels and operable for providing a second electrical signal of a second predetermined time period to said modulation means for selecting the other of the remote terminal unit channels.

Claim 10

In a data processing system having a central processing unit operatively connected online to a command data set at one end of a telephone network and through a switching data set at the other end of the telephone network to either one of two different remote terminal unit channels, the command data set comprising: oscillation means generating a series of pulses at either one of two different pulse frequencies, modulation means operatively coupled to said oscillation means for modulating data information over said telephone lines, channel selection means responsive to command signals from the central processing unit for selecting one or the other of the remote terminal unit channels and operable for generating a channel selection control signal in response to said selection, and a timer responsive to said channel selection control signal and said oscillation means and operable for providing a first electrical signal of a first predetermined time period to said modulation means for selecting one of the remote terminal unit channels and operable for providing a second electrical signal of a second predetermined time period to said modulation means for selecting the other of the remote terminal unit channels.

Claim 11

In the command data set according to claim 7 wherein said timer is a ring counter and said first predetermined time period comprises a count which is less than the count of said second predetermined time period.