Method and apparatus for coupling computer work stations

Claim 3

The apparatus of claim 1 further com­prising an adapter coupled to each said work station for converting a multi-wire line from said work station to a two-wire telephone line.

Claim 4

The apparatus of claim 1 further com­prising means for carrying both voice and data on said telephone lines.

Claim 5

The apparatus of claim 3 wherein said means for carrying both voice and data comprises a high-pass filter coupled at an input to said hub and a low-pass filter coupled between said input and an output to a telephone exchange.

Claim 6

The apparatus of claim 4 further com­prising an adapter at said work station for converting a multi-wire line from said work station to a two-wire telephone line, said adapter having a high-pass filter coupling an input from said hub to said adapter and a low-pass filter coupling said input to an optional telephone.

Claim 7

The apparatus of claim 5 wherein said adapter further comprises: a transformer having a primary winding coupled to said high pass filter and first and second secondary windings; a comparator having an input coupled to said first secondary winding; means, coupled to an output of said comparator, for separating a clock signal from a data signal from said comparator output and providing separate clock and data outputs; an RS422 driver having inputs coupled to said clock and data outputs of said comparator and having outputs coupled to a RS422 connector; an RS422 receiver having inputs coupled to said RS422 port; and means, coupled to outputs of said RS422 receiver, for combining separate clock and data signals from said RS422 receiver onto a differential pair of output lines, said output lines being coupled to said second secondary winding of said transformer.

Claim 8

The apparatus of claim 1 wherein said means for determining comprises a detector for monitor­ing a first transmission on said telephone lines.

Claim 9

The apparatus of claim 1 wherein said means for providing transmissions from said master work station to all of said cluster work stations comprises a receiver coupled to a telephone line connected to said master work station, means for coupling said receiver to a master bus, a plurality of transmitters coupled to telephone lines to each of said cluster work stations, and a plurality of means for coupling said master bus to said transmitters.

Claim 10

A hub for coupling a plurality of cluster work stations to a master work station over two-wire telephone lines, comprising: a plurality of channels corresponding to said work stations, each having a transmitter and a receiver; a master bus coupled to all of said channels; a cluster bus coupled to all of said channels; means for determining which of said channels is coupled to said master work station; means for coupling said transmitter in said master channel to said master bus and said trans­mitter in the remaining channels to said cluster bus; and means for coupling said receiver in said master channel to said cluster bus and said receivers in said remaining channels to said master bus.

Claim 11

A hub for coupling a plurality of cluster work stations to a master work station over two-wire telephone lines, comprising: a plurality of channels corresponding to said work stations, each having a transmitter and a receiver; a master bus coupled to all of said channels; a cluster bus coupled to all of said channels; means for determining which of said channels is coupled to said master work station; means for coupling said transmitter in said master channel to said master bus and said trans­mitter in the remaining channels to said cluster bus; and means for coupling said receiver in said master channel to said cluster bus and said receivers in said remaining channels to said master bus.

Claim 12

A hub for coupling a plurality of cluster work stations to a master work station over two-wire telephone lines, comprising: a microprocessor for controlling the operation of said hub; a timing circuit for providing clock signals in said hub; and a plurality of channels corresponding to said work stations, each channel including a high pass filter adapted to couple at a first end to a telephone line to one of said work stations, a low pass filter having a first end coupled to said telephone line and a second end adapted to couple to an external telephone exchange, a transformer having a primary winding and first and second secondary windings, said primary winding being coupled to a second end of said high pass filter, a detector having an input coupled to said first secondary winding, a master bus, said master bus being coupled to all of said channels, a cluster bus, said cluster bus being coupled to all of said channels, a first gate for coupling said detector to said master bus, said first gate having an enable input coupled to said microprocessor, a second gate for coupling said detector to said cluster bus, said second gate having an enable input coupled to said microprocessor, a multiplexer having first and second inputs coupled to said master bus and said cluster bus, respectively, said multiplexer having a select input coupled to said microprocessor for selecting one of said first and second inputs for coupling to a multiplexer output, and a third gate for coupling said multiplexer output to said second secondary winding of said transformer, said third gate having an enable input coupled to said microprocessor.

Claim 13

A hub for coupling a plurality of cluster work stations to a master work station over two-wire telephone lines, comprising: a microprocessor for controlling the operation of said hub; a timing circuit for providing clock signals in said hub; and a plurality of channels corresponding to said work stations, each channel including a high pass filter adapted to couple at a first end to a telephone line to one of said work stations, a low pass filter having a first end coupled to said telephone line and a second end adapted to couple to an external telephone exchange, a transformer having a primary winding and first and second secondary windings, said primary winding being coupled to a second end of said high pass filter, a detector having an input coupled to said first secondary winding, a master bus, said master bus being coupled to all of said channels, a cluster bus, said cluster bus being coupled to all of said channels, a first gate for coupling said detector to said master bus, said first gate having an enable input coupled to said microprocessor, a second gate for coupling said detector to said cluster bus, said second gate having an enable input coupled to said microprocessor, a multiplexer having first and second inputs coupled to said master bus and said cluster bus, respectively, said multiplexer having a select input coupled to said microprocessor for selecting one of said first and second inputs for coupling to a multiplexer output, and a third gate for coupling said multiplexer output to said second secondary winding of said transformer, said third gate having an enable input coupled to said microprocessor.