Low cost ISDN switch

A method of selecting, from a plurality of devices, a device for coupling to a data line, comprising the steps of:

• receiving information from the data line;
• examining the information to determine the presence of device identifier information;
• and
• utilizing a content addressable memory to identify a device from the device identifier information;
• and
• enabling a buffer, associated with the identified device, such that said buffer provides an operative coupling of the identified device with the data line.

A switch for selecting one of a plurality of devices for coupling to a data line, said switch comprising:

• a switch controller, for coupling to each of a plurality of devices;
• a device selector, coupled to the switch controller, the device selector including a content addressable memory containing device information;
• and
• a plurality of buffers, each of said buffers having an enabling input coupled to the device selector, each buffer coupled to the data line and each buffer for coupling to a device;
• such that when a device coupled to the switch controller signals a desire to be coupled to the data line, the switch controller signals to the device selector to utilize the content addressable memory to identify the device, the device selector sending an enable signal to the buffer associated with the identified device to be coupled to the data line, thereby operatively coupling the data line to said identified device.

A method for selecting one of a plurality of devices for coupling to a data line, the method comprising the steps of:

• signaling from a device to a switch controller the device's desire to be coupled to the data line;
• signaling from the switch controller to a device selector, which includes a content addressable memory, for said device selector to utilize said content addressable memory for identifying said device, and to send an enable signal to a buffer coupled to said identified device;
• and
• enabling said buffer to operatively couple said identified device to said data line.

A switch for selecting, from among a plurality of devices, a device to be coupled to a data line, said switch comprising:

• a data line receiver, for coupling to a data line;
• a data line interrogator and switch controller, coupled to the data line receiver;
• a device identifier, coupled to the data line receiver and the data line interrogator and switch controller;
• and
• a plurality of buffers, each buffer having an enabling input coupled to the device identifier, each buffer being coupled to the data line, and each buffer for coupling to a device;
• such that when information is received by the data line receiver and evaluated by the data line interrogator and switch controller to be device identification information, the data line interrogator and switch controller signals the device identifier to enable a buffer associated with a device so identified to provide for an operative coupling of the data line and the identified device;
• wherein the coupling of each buffer to the data line comprises a first additional buffer having an enabling input, said first additional buffer being coupled to the data line receiver, and said enabling input of said first additional buffer being coupled to the data line interrogator and switch controller.

A switch for selecting, from among a plurality of devices, a device to be coupled to a data line, said switch comprising:

• means, coupled to said data line, for receiving information;
• means, coupled to said means for receiving information, for evaluating whether said information comprises device identification information;
• means, coupled to said means for receiving information and said means for evaluating, and including a content addressable memory containing device information, for utilizing the content addressable memory to identify a device associated with said device identification information and generating an enable signal associated with the identified device;
• and
• a plurality of buffers, each buffer having an enabling input coupled to said means for utilizing and generating, each buffer being coupled to said data line, and each buffer for coupling to a device, whereby when a buffer receives an enable signal from said means for utilizing and generating, said buffer provides an operative coupling of said data line and an identified device.

A switch for selecting one of a plurality of devices for coupling to a data line, said switch comprising:

• means, for coupling to each of a plurality of devices, for receiving from a device a request to be coupled to the data line;
• means, coupled to said means for receiving, for generating an enable signal associated with said device, said means for generating including a content addressable memory containing device information;
• and
• means, said means coupled to the data line and for coupling to a device, and having an enabling input coupled to said means for generating, for receiving said enable signal and, in response thereto, operatively coupling the data line with said device.

A switch for selecting one of a plurality of devices for coupling to a data line, said switch comprising:

• a switch controller, for coupling to each of a plurality of devices;
• a device selector, coupled to the switch controller;
• and
• a plurality of buffers, each of said buffers having an enabling input coupled to the device selector, each buffer coupled to the data line and each buffer for coupling to a device;
• such that when a device coupled to the switch controller signals a desire to be coupled to the data line, the switch controller signals the device selector to send an enable signal to the buffer associated with the device to be coupled to the data line, thereby operatively coupling the data line to said device;
• wherein the coupling of each buffer to the data line includes a first additional buffer having an enabling input coupled to the switch controller.

A switch for selecting, from among a plurality of devices, a device to be coupled to a data line, said switch comprising:

• means, coupled to said data line, for receiving information;
• means, coupled to said means for receiving information, for evaluating whether said information comprises device identification information;
• means, coupled to said means for receiving information and said means for evaluating, for identifying a device associated with said device identification information and generating an enable signal associated with the identified device;
• and
• a plurality of buffers, each buffer having an enabling input coupled to said means for identifying and generating, each buffer being coupled to said data line, and each buffer for coupling to a device, whereby when a buffer receives an enable signal from said means for identifying and generating, said buffer provides an operative coupling of said data line and an identified device, wherein the coupling of each buffer to the data line includes a first additional buffer having an enabling input, said first additional buffer being coupled to said means for receiving, and said enabling input of said first additional buffer being coupled to said means for identifying and generating.