Multi-port LAN switch for a token-ring network

• US 5,680,397 A
• Filed: 03/13/1995
• Issued: 10/21/1997
• Est. Priority Date: 03/13/1995
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Christensen, Kenneth J., Rehquate, Rudolf E., Dagher, Jerry, Stammely, Thomas, Bevill, Beymer Jr., Noel, Francis E.
• Primary Examiner(s): NGUYEN, CHAU T
• Application Number:
  US08/402,740
• Time in Patent Office: 953 Days
• Field of Search: 370/225, 370/228, 370/275, 370/278, 370/258, 370/254, 370/294, 370/296, 370/323, 370/257, 370/421, 370/537, 370/540, 370/434, 370/420, 370/425, 370/424, 370/222, 370/452, 340/825.05, 395/200.21
• US Class Current: 370/421
• CPC Class Codes: H04L 12/42 Loop networks
• CPC Class Codes: H04L 12/44 Star or tree networks

Abstract

A multi-port LAN switch is provided that enables attached network devices to both communicate directly and to insert into a token-ring network through an attached concentrator. Each port of the multi-port LAN switch has a first transformer, a second transformer, and a switching system. The first transformer has a first winding connected to a first connection of the port. The second transformer has a first winding connected to a second connection of the port. The switching system switches to a port mode or an adapter mode as a function of a mode signal transmitted to the port. In the adapter mode, the switching system connects a second winding of the first transformer to a transmitter circuit in the port, and its connects a second winding of the second transformer to a receiver circuit in the port. In the port mode, the switching system connects the second winding of the first transformer to the receiver circuit in the port, and it connects the second winding of the second transformer to the transmitter circuit in the port. Each port of the multi-port LAN switch further includes a DC voltage source that is switchably connected to the first connection of the port through a first switch. Each port further includes a second switch that connects the second connection of the port to a DC return-path in a first position, and connects the second connection to the first connection when in a second position.

Claims

1. A data transfer unit for a network, each port of the data transfer unit having a first port connection, a second port connection, a transmitter circuit and a receiver circuit, each port of the data transfer unit comprising:

a first transformer having a first winding connected to the first port connection, and a second winding;

a second transformer having a first winding connected to the second port connection, and a second winding;

a switching system that switches the port to a first mode or a second mode as a function of a mode signal for that port, wherein the switching system in the first mode connects the second winding of the first transformer to the transmitter circuit and the second winding of the second transformer to the receiver circuit, and wherein the switching system in the second mode connects the second winding of the first transformer to the receiver circuit and the second winding of the second transformer to the transmitter circuit.

2. A data transfer unit for a network according to claim 1, each port further comprising:

a first switch;

a DC voltage source switchably connected to the first port connection through the first switch; and

a second switch having a first and second position, and connecting the second port connection to a DC return-path in the first position and to the first port connection in the second position.

3. A data transfer unit for a network according to claim 1, wherein every transmitter circuit is interconnected with every receiver circuit such that each port can communicate with every other port.

4. A data transfer unit for a network according to claim 1, wherein a port is connected to a data transfer unit.

5. A data transfer unit for a network according to claim 1, wherein a port is connected to a standard adapter.

6. A data transfer unit for a network according to claim 1, wherein a port is connected to a concentrator.

7. A data transfer unit for a network unit according to claim 1, wherein the data transfer unit is a multi-port LAN switch.

8. A data transfer unit for a network, each port of the data transfer unit having a second port connection, a first port connection, a transmitter circuit and a receiver circuit, each port of the data transfer unit comprising:

a switching system that switches the port to a first mode or a second mode as a function of a mode signal for that port, wherein the switching system switched to the first mode connects the first port connection to the transmitter circuit and the second port connection to the receiver circuit, and wherein the switching system switched to the second mode connects the first port connection to the receiver circuit and the second port connection to the transmitter circuit;

a first switch;

a DC voltage source switchably connected to the first port connection through the first switch; and

a second switch having a first and second position, and connecting the second port connection to a DC return-path in the first position and to the first port connection in the second position.

9. A data transfer unit for a network according to claim 8, wherein every transmitter circuit is interconnected with every receiver circuit such that each port can communicate with every other port.

10. A data transfer unit for a network according to claim 8, wherein a port is connected to a data transfer unit.

11. A data transfer unit for a network according to claim 8, wherein a port is connected to a standard adapter.

12. A data transfer unit for a network according to claim 8, wherein a port is connected to a concentrator.

13. A data transfer unit for a network according to claim 8, wherein the data transfer unit is a multi-port LAN switch.

14. A data communications networking system comprising:

a plurality of network adapters;

a concentrator connecting one or more of the plurality of network adapters to form a token-ting network; and

a first data transfer unit having one of the plurality of network adapters connected to a first port of the data transfer unit and the concentrator connected to a second port of the data transfer unit, each port of the first data transfer unit having a first port connection, a second port connection, a transmitter circuit and a receiver circuit, and further each port of the data transfer unit including;

a switching system that switches the port to a first mode or a second mode as a function of a mode signal for that port, wherein the switching system switched to the first mode connects the first port connection to the transmitter circuit and the second port connection to the receiver circuit, and wherein the switching system switched to the second mode connects the first port connection to the receiver circuit and the second port connection to the transmitter circuit;

a first switch;

a DC voltage source switchably connected to the first port connection through the first switch; and

a second switch having a first and second position, and connecting the second port connection to a DC return-path in the first position and to the first port connection in the second position.

15. A data communications networking system according to claim 14, wherein every transmitter circuit is interconnected with every receiver circuit such that each port can communicate with every other port.

16. A data communications networking systems according to claim 14, wherein a third port of the data transfer unit is connected to a first port of a second data transfer unit.

17. A data communications networking system according to claim 14, wherein a first mode signal switches the switching system of the first port of the first data transfer unit to the second mode.

18. A data communications networking system according to claim 14, wherein a second mode signal switches the switching system of the second port of the first data transfer unit to the first mode.

19. A data communications networking system according to claim 14, wherein the first data transfer unit is a LAN switch.