Dynamic address assignments to serially connected devices

• US 5,680,113 A
• Filed: 02/24/1995
• Issued: 10/21/1997
• Est. Priority Date: 02/24/1995
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Allen, James Johnson, Verne, Robert D.
• Primary Examiner(s): Holloway, III, Edwin C.
• Application Number:
  US08/393,976
• Time in Patent Office: 970 Days
• Field of Search: 340/825.05, 340/825.52, 340/825.53, 340/825.02, 395/183.08, 370/85.11, 370/401
• US Class Current: 340/9.16
• CPC Class Codes: H04L 61/5038 for local use, e.g. in LAN or USB networks, or in a controller area network [CAN]
• CPC Class Codes: H04L 61/5046 Resolving address allocation conflicts; Testing of addresses testing when self-assigning an address H04L61/5092

Abstract

Dynamic address assignment and reconfiguration of serially connected addressable device components of a network system using interchangeable cables terminated by plugs. Successive pairs of the devices are coupled with identical cables having the same offset cross-connected wiring between the terminating plugs, but which establish a unique address for the device to which connected depending on the position of the device in a chain of connected devices without requiring changes to the devices per se, e.g., jumpers or switches. The bus structure requires only a single port per device and removal, failure, or replacement of a device does not affect nor impair the proper operation of the other devices.

Claims

1. An address allocation apparatus for electrically coupling a first and second electronic device and assigning a unique address to said first and said second electronic device, comprising:

a first plug having a first plurality of pins connecting to said first electronic device;

a second plug having a second plurality of pins connecting to said second electronic device; and

a cable coupler cross-coupling said first plurality of pins of said first plug to said second plurality of pins of said second plug,

said first plug having a pin n of said first plurality of pins coupled to a pin n+1 of said second plurality of pins of said second plug through said cable coupler,

said second plug having a front pin side and a rear pin side, said front pin side containing said second plurality of pins for connecting to said second device, said rear pin side detachably receives a first plug of a second address allocation apparatus, said second address allocation apparatus having at least one set of pins, said rear pin side for electrically coupling the second plurality of pins of said second plug to the at least one set of pins of said second address allocation apparatus.

2. The apparatus of claim 1, wherein said first electronic device and said second electronic device are operating in a computer network.

3. A method of determining the addresses of individual electronic devices electronically connected together by a cable, each electronic device having a unique physical location along the length of the cable, comprising the steps of:

generating address signals for said electronic devices by cross-coupling the electrical connections between said devices with a cable adapted to receive another cable piggy-back, said address signals uniquely corresponding to the unique physical location of each of said electronic devices in the system;

detecting said address signals within said electronic devices; and

decoding said address signals within in said electronic devices.

4. The method of claim 3, further comprising the steps of:

generating a module present signal in each electronic device based on said address signal of the electronic device and an operating status of the electronic device,

reading in each electronic device the module present signals generated by other electronic devices,

comparing periodically the module present signals generated by other electronic devices to determine any change in number of electronic devices present.

5. A method for determining a change in number of devices on a network, comprising the steps of:

connecting each device to the network through a cable having a piggy-back interconnection plug;

assigning a unique physical address to each device interconnected in the network by cross-coupling the address signals in the cable;

generating a module present signal in each device corresponding to a unique address for said device;

transmitting the module present signal of each device onto the cable;

in each device reading all of said module present signals generated by each device; and

comparing periodically all of said module present signals, thereby determining any changes in number of devices present.

6. An address allocation apparatus for electrically coupling a first and second electronic device and assigning a unique address to said first and said second electronic device, comprising:

a first plug having a first plurality of pins connecting to said first electronic device;

a second plug having a second plurality of pins connecting to said second electronic device; and

a cable coupler cross-coupling said first plurality of pins of said first plug to said second plurality of pins of said second plug,

said first plug having M total pins and N address pins, wherein M>

N, a pin z of said N address pins of said first plurality of pins is coupled through said cable coupler to a pin z+1 of said N address pins for each N address pins of said second plurality of pins of said second plug,

the Nth pin of said first plug is unconnected, and a first pin of said N address pins is coupled to an Mth pin within said first plug,

said second plug having a front pin side and a rear pin side, said front pin side containing said second plurality of pins for connecting to said second device, said rear pin side detachably receives a first plug of a second address allocation apparatus, said second address allocation apparatus having at least one set of pins, said rear pin side for electrically coupling the second plurality of pins of said second plug to the at least one set of pins of said second address allocation apparatus.