Multipoint data communications systems utilizing multipoint switches

Claim 2

In a multipoint data communications system, a multipoint switch including means responsive to each of a plurality of polling signal sequences on a signaling path from a central station for extending the signaling path to a selected one of a plurality of remote terminals, the multipoint switch further including means responsive to the polling sequence for blinding the multipoint switch to signals on the signaling path, characterized in that the blinding means further includes means for unblinding the multipoint switch in response to the absence of signals on the signaling path for a predetermined interval.

Claim 3

In a multipoint data communications system, in accordance with claim 1, wherein each of the plurality of polling sequences includes a remote terminal address portion defining a selected one of the remote terminals and a remote terminal command portion common to all remote terminals, the multipoint switch further including means responsive to the remote terminal address portion for enabling the extending means and the selected remote terminal including means responsive to the remote terminal command portion for communicating with the central station.

Claim 4

In a multipoint data communications system, in accordance with claim 2, wherein the remote terminal command portion includes a single frequency tone of constant duration dollowed by a silent interval of constant duration, the single frequency tone and the silent interval being common to each remote terminal command portion, the remote terminal further including means responsive to the single frequency tone followed by the silent interval for enabling the communicating means.

Claim 5

In a multipoint data communications system, in accordance with claim 2, wherein the communicating means includes means responsive to the remote terminal enabling means for transmitting data messages to the central station, means for determining the end of each message transmitted to the central station and means jointly responsive to the remote terminal enabling means and to the determining means for receiving data messages from the central station.

Claim 6

In a multipoint data communications system, in accordance with claim 1, wherein the multipoint switch further includes means for detecting signal transmission sequences on the signaling path longer in duration than a predetermined maximum duration of time, and means responsive to the detection of the transmission sequences exceeding the predetermined maximum duration of time for breaking the signaling path.

Claim 7

A multipoint data communications system, including a central station, a multipoint switch and a plurality of remote terminals, the central station including means for transmitting a polling sequence onto a signaling path to select one of the plurality of remote terminals, the polling sequence including a remote termial address portion defining the selected one of the remote terminals and a remote terminal command portion common to all remote terminals, the system further including, means included in the multipoint switch and responsive to the remote terminal address portion for extending the signaling path to the selecteD one of the remote terminals defined by the remote terminal address portion, and means included in the selected remote terminal and responsive to the remote terminal command portion for communicating with the central station.

Claim 8

A multipoint data communications system, including a central station, a multipoint switch and a plurality of remote terminals, the central station including means for transmitting a polling sequence onto a signaling path to select one of the plurality of remote terminals, the polling sequence including a remote termial address portion defining the selected one of the remote terminals and a remote terminal command portion common to all remote terminals, the system further including, means included in the multipoint switch and responsive to the remote terminal address portion for extending the signaling path to the selecteD one of the remote terminals defined by the remote terminal address portion, and means included in the selected remote terminal and responsive to the remote terminal command portion for communicating with the central station.

Claim 9

A multipoint data communications system in accordance with claim 6 wherein the remote terminal command portion includes a single frequency tone of constant duration followed by a silent interval of constant duration, the single frequency tone and the silent interval being common to each remote terminal command portion, the remote terminal further including means responsive to the single frequency tone followed by the silent interval for enabling the communicating means.

Claim 10

A multipoint data communications system in accordance with claim 6 wherein the multipoint switch further includes means responsive to the remote terminal address portion for blinding the multipoint switch to signals on the signaling path, the blinding means including means for unblinding the multipoint switch in response to the absence of signals on the signaling path for a fixed interval of time.

Claim 11

A multipoint data communications system in accordance with claim 8 wherein the remote terminal further includes means for transmitting data messages to the central station, means for determining the end of each data message transmitted to the central station, and means jointly responsive to the enabling means and to the determining means for receiving data messages from the central station.

Claim 12

A multipoint data communications system in accordance with claim 6 wherein the multipoint switch further includes means for detecting signal transmission sequences on the signaling path greater in duration than a predetermined maximum duration of time, and means responsive to the detection of the transmission sequences exceed the predetermined maximum duration of time for breaking the signaling path.

Claim 13

In a multipoint data communications system, a central station, a multipoint switch and a plurality of remote terminals, the multipoint switch including means responsive to each of a plurality of polling signal sequences on a signaling path from the central station for extending the signaling path to a selected one of the plurality of remote terminals, each remote terminal including means for transmitting data messages on the signaling path to the central station and means for receiving data messages on the signaling path from the central station, the remote terminal further including, means for detecting the extension of the signaling path to the selected remote terminal, means for determining the end of each data message transmitted to the central station, and means jointly responsive to the determining means and to the detecting means for enabling the receiving means.

Claim 14

In a multipoint data communications system, a central station, a multipoint switch and a plurality of remote terminals, the multipoint switch including means responsive to each of a plurality of polling signal sequences on a signaling path from the central station for extending the signaling path to a selected one of the plurality of remote terminals, each remote terminal including means for transmitting data messages on the signaling path to the central station and means for receiving data messages on the signaling path from the central station, the remote terminal further including, means for detecting the extension of the signaling path to the selected remote terminal, means for determining the end of each data message transmitted to the central station, and means jointly responsive to the determining means and to the detecting means for enabling the receiving means.

Claim 15

In a multipoint data communications system, in accordance with claim 11, wherein the polling sequence includes a remote terminal address portion defining an individual one of the plurality of remote terminals and a remote terminal command portion common to all remote terminals, the system further including a multipoint switch including means responsive to the remote terminal address portion for extending the signaling path to the individual remote terminal, the multipoint switch further including means responsive to the remote terminal address portion for blinding the multipoint switch to signals on the signaling path and means for unblinding the multipoint switch in response to the absence of signals on the signaling path for a predetermined interval of time.

Claim 16

In a multipoint data communications system, in accordance with claim 12, wherein the remote terminal command portion includes a single frequency tone of constant duration followed by a silent interval of constant duration, the single frequency tone and the silent interval being common to each remote terminal command portion, the remote terminal further including means responsive to the single frequency tone followed by the sIlent interval for enabling communication apparatus at the central station.

Claim 17

In a multipoint data communications system, in accordance with claim 11, wherein the multipoint switch further includes means for detecting signal transmission sequences on the signaling path greater in duration than a predetermined maximum duration of time, and means responsive to the detection of the transmission sequences exceeding the predetermined maximum duration of time for breaking the signaling path.

Claim 18

A multipoint data communications system including a central station, a multipoint switch and a plurality of remote terminals, the multipoint switch including means responsive to a polling signal sequence transmitted on a signaling path from the central station for extending the signaling path from the multipoint switch to a selected one of the plurality of remote terminals, and polling sequence including a remote terminal address portion defining the selected one of the remote terminals and a remote terminal command portion common to all remote terminals, the system further including, means responsive to the remote terminal address portion for blinding the multipoint switch to signals on the signaling path for an interval of time, and means included in the remote terminal and responsive to the remote terminal command portion for communicating with the central station.

Claim 19

A multipoint data communications system including a central station, a multipoint switch and a plurality of remote terminals, the multipoint switch including means responsive to a polling signal sequence transmitted on a signaling path from the central station for extending the signaling path from the multipoint switch to a selected one of the plurality of remote terminals, and polling sequence including a remote terminal address portion defining the selected one of the remote terminals and a remote terminal command portion common to all remote terminals, the system further including, means responsive to the remote terminal address portion for blinding the multipoint switch to signals on the signaling path for an interval of time, and means included in the remote terminal and responsive to the remote terminal command portion for communicating with the central station.

Claim 20

A multipoint data communications system, in accordance with claim 15, wherein the remote terminal command portion includes a single frequency tone of constant duration followed by a silent interval of constant duration, the single frequency tone and the silent interval being common to each remote terminal command portion, the remote terminal further including means responsive to the single frequency tone followed by the silent interval for enabling the communicating means.

Claim 21

A multipoint data communications system in accordance with claim 16 wherein the remote terminal further includes means responsive to the enabling means for transmitting data messages to the central station, means for determining the end of each data message transmitted to the central station, and means jointly responsive to the enabling means and to the determining means for receiving data messages from the central station.

Claim 22

A multipoint data communications system in accordance with claim 15 wherein the multipoint switch further includes means for detecting signal transmission sequences on the signaling path greater in duration than a predetermined maximum duration of time, and means responsive to the detection of the transmission sequences exceeding the predetermined maximum duration of time for breaking the signaling path.

Claim 25

A method for establishing a signaling path in accordance with claim 19 wherein the terminal selection signals include a terminal address portion defining a selected one of the remote terminals and a terminal command portion common to all remote terminals, the method further including the steps of, detecting the occurrence of the terminal command portion followed by the absence of signals on the signaling path and enabling communications apparatus at the selected remote terminal defined by the terminal address portion.

Claim 28

A method for polling in accordance with claim 21 wherein the extending step further includes the steps of, blinding the multipoint switch to signals on the extended signaling path, detecting the absence of signals on the extended signaling path for a predetermined interval of time and unblinding the multipoint switch.

Claim 29

A multipoint data communications system including a central station, a primary multipoint switch, a plurality of secondary multipoint switches and a plurality of remote terminals, the central station including means for transmitting a primary polling sequence onto the signaling path followed by a secondary polling sequence, the primary polling sequence including a multipoint switch address portion defining a selected one of the secondary multipoint switches, the secondary polling sequence including a remote terminal address portion defining a selected one of the remote terminals and a remote terminal command portion common to all remote terminals, the primary multipoint switch including means responsive to the multipoint switch address portion for extending the primary multipoint switch to the secondary multipoint switch, the secondary multipoint switch including means responsive to the remote terminal address portion for further extending the extended signaling path from the secondary multipoint switch to a selected one of the plurality of remote terminals, the system further including, means included in the primary multipoint switch and responsive to the multipoint switch address portion for blinding the primary multipoint switch to signals on the extended signaling path, means included in the secondary multipoint switch and responsive to the remote terminal address portion for blinding the secondary multipoint switch to signals on the further extended signaling path, and means included in the remote terminal and responsive to the remote terminal command portion for communicating with the central station.

Claim 30

A multipoint data communications system including a central station, a primary multipoint switch, a plurality of secondary multipoint switches and a plurality of remote terminals, the central station including means for transmitting a primary polling sequence onto the signaling path followed by a secondary polling sequence, the primary polling sequence including a multipoint switch address portion defining a selected one of the secondary multipoint switches, the secondary polling sequence including a remote terminal address portion defining a selected one of the remote terminals and a remote terminal command portion common to all remote terminals, the primary multipoint switch including means responsive to the multipoint switch address portion for extending the primary multipoint switch to the secondary multipoint switch, the secondary multipoint switch including means responsive to the remote terminal address portion for further extending the extended signaling path from the secondary multipoint switch to a selected one of the plurality of remote terminals, the system further including, means included in the primary multipoint switch and responsive to the multipoint switch address portion for blinding the primary multipoint switch to signals on the extended signaling path, means included in the secondary multipoint switch and responsive to the remote terminal address portion for blinding the secondary multipoint switch to signals on the further extended signaling path, and means included in the remote terminal and responsive to the remote terminal command portion for communicating with the central station.

Claim 31

A multipoint data communications system in accordance with claim 23 wherein the primary and secondary multipoint switches further include means for unblinding the primary and secondary multipoint switches in response to the absence of signals on the signaling path for a predetermined interval of time.

Claim 32

A multipoint data communications system, in accordance with claim 23, wherein the remote terminal command portion includes a single frequency tone of constant duration followed by a silent interval of constant duration, the single frequency tone and the silent interval being common to each remote terminal command portion, the remote terminal further including means responsive to the single frequency tone followed by the silent interval for enabling the communicating means.

Claim 33

A multipoint data communications system in accordance with claim 25 wherein the remote terminal further includes means responsive to the enabling means for transmitting data messages to the central station, means for determining the end of each data message transmitted to the central station, and means jointly responsive to the enabling means and to the determining means for receiving data messages from the central station.

Claim 34

A multipoint data communications system in accordance with claim 26 wherein both the primary and secondary multipoint switches further include means for detecting signal transmission sequences on the signaling path greater in duration than a predetermined maximum duration of time, and means responsive to the detection of the transmission sequences exceeding the predetermined maXimum duration of time for breaking the signaling path.