Extending universal serial bus to allow communication with USB devices at a remote location

• US 6,708,247 B1
• Filed: 07/20/2000
• Issued: 03/16/2004
• Est. Priority Date: 07/21/1999
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: ClearCube Technology Incorporated
• Inventors: Barret, Dan, Heller, Andrew, Barron, Mike
• Primary Examiner(s): Ray, Gopal C.
• Application Number:
  US09/619,989
• Time in Patent Office: 1,335 Days
• Field of Search: 710/33, 710/104, 710/300, 710/100, 710/305, 710/313, 710/63, 710/106, 710/62, 714/1, 714/30, 709/218, 709/253, 370/465
• US Class Current: 710/313
• CPC Class Codes: G06F 13/4286 using a handshaking protocol, e.g. RS232C link

Abstract

System and method for communicating data over a remote Universal Serial Bus (USB) which may be used in systems wherein a host computer communicates with one or more remote USB devices. A host computer system may be coupled to a USB Remote Root Hub through a USB Extension (USBX) bus, providing the capability to control peripheral USB devices beyond the typical range of USB as specified in the USB specification. The USB Remote Root Hub may be coupled to the USB peripheral devices through the USB and may be located in the vicinity of the peripherals subject to standard USB distance limitations, and may thus be located remotely from the host.

Claims

1. A system for communicating data over a Universal Serial Bus (USB), the system comprising:

a host computer system including a processor and a memory;

a host controller coupled to the host computer system;

a first bus which is coupled to the host controller;

a USB Remote Root Hub which is coupled to the first bus, wherein the USB Remote Root Hub is further coupled to the USB; and

at least one USB device, wherein the at least one USB device is coupled to the USB;

wherein the host controller, the first bus, and the USB Remote Root Hub are operable to allow communication between the host computer system and the USB device over a distance which is greater than a maximum distance specified in a USB protocol specification.

2. The system of claim 1, wherein the host computer system comprises the host controller.

3. The system of claim 1,

wherein the host controller, the first bus, and the USB Remote Root Hub are operable to allow communication between the host computer system and the USB device;

wherein the first bus has a length greater than about 5 meters.

4. The system of claim 1,

wherein the memory of the host computer system comprises a USB driver program, and wherein the processor in the host computer system is operable to execute the USB driver program.

5. The system of claim 1,

wherein the host controller presents a USB compliant interface to the USB driver program.

6. The system of claim 1,

wherein the memory of the host computer system comprises a USB driver program, and wherein the processor in the host computer system is operable to execute the USB driver program;

and

wherein the host controller presents a USB compliant interface to the USB driver program.

7. The system of claim 1, wherein the host controller and the first bus are substantially transparent to the USB driver program.

8. The system of claim 1, wherein the host controller and the first bus are substantially transparent to the USB Remote Root Hub.

9. The system of claim 1,

wherein the USB Remote Root Hub is operable to:

receive a data packet from the USB device through the USB bus;

transmit the data packet to the host computer system after receiving the data packet; and

send an acknowledgement (ACK) to the USB device after receiving the data packet.

10. The system of claim 9,

wherein the host computer system is operable to transmit a host acknowledgement to the USB Remote Root Hub in response to the host computer system receiving the data packet transmitted from the USB Remote Root Hub.

11. The system of claim 10,

wherein the USB Remote Root Hub is operable to send an acknowledgement (ACK) to the USB device prior to the USB Remote Root Hub receiving the host acknowledgement from the host computer system.

12. The system of claim 9,

wherein the host computer system is operable to transmit a host acknowledgement to the USB Remote Root Hub in response to the host computer system successfully receiving the data packet from the USB Remote Root Hub;

wherein the USB Remote Root Hub is operable to send an acknowledgement (ACK) to the USB device prior to the USB Remote Root Hub receiving the host acknowledgement from the host computer system.

13. The system of claim 12,

wherein, if the host acknowledgement is received from the host computer system before a time-out condition occurs, then the USB Remote Root Hub is operable to receive a subsequent data packet from the USB device.

14. The system of claim 12,

wherein, if the host acknowledgement is not received from the host computer system before the time-out condition occurs, then the USB Remote Root Hub is operable to re-send the data packet to the host computer system one or more times.

15. The system of claim 14,

wherein, if the host acknowledgement is not received from the host computer system after the USB Remote Root Hub re-sends the data packet to the host computer system a maximum number of times, the USB Remote Root Hub is operable to execute an error routine.

16. The system of claim 1,

wherein the USB device comprises one of a display device, a pointing device, a keyboard, a disc drive, an optical drive, a printer, a fax machine, a scanner, or a tape drive.

17. The system of claim 1, wherein the first bus is a USBX bus.

18. A method for communicating data over a remote Universal Serial Bus (USB), the method comprising:

receiving a data packet from a USB device through a USB bus;

transmitting the data packet to a host computer system over a first bus;

transmitting an acknowledgement (ACK) to the USB device over the USB bus, wherein said transmitting of the ACK to the USB device occurs prior to a host acknowledgement being received from the host computer system acknowledging receipt of the data packet;

wherein the first bus has a length greater than about 5 meters.

19. The method of claim 18,

wherein the first bus has a length greater than a maximum distance specified in a USB protocol specification.

20. The method of claim 18,

wherein the transmitting the data packet to the host computer system over the first bus comprises transmitting the data packet to a host controller, wherein the host controller is coupled to the host computer system.

21. The method of claim 20,

wherein the host computer system comprises the host controller.

22. The method of claim 18,

wherein the transmitting the data packet to the host computer system over the first bus comprises transmitting the data packet to a host controller, wherein the host controller is coupled to the host computer system;

and

wherein the first bus has a length greater than a maximum distance specified in a USB protocol specification.

23. The method of claim 22,

wherein the host computer system comprises the host controller.

24. The method of claim 22,

wherein the host computer system comprises a processor and a memory, wherein the memory of the host computer system comprises a USB driver program, and wherein the processor in the host computer system is operable to execute the USB driver program.

25. The method of claim 24,

wherein the host controller presents a USB compliant interface to the USB driver program.

26. The method of claim 24,

wherein the host controller and the first bus are substantially transparent to the USB driver program.

27. The method of claim 22,

wherein the memory of the host computer system comprises a USB driver program, and wherein the processor in the host computer system is operable to execute the USB driver program;

and

wherein the host controller presents a USB compliant interface to the USB driver program.

28. The method of claim 27, wherein the host controller and the first bus are substantially transparent to the USB driver program.

29. The method of claim 18,

wherein the host computer system comprises a processor and a memory, wherein the memory of the host computer system comprises a USB driver program, and wherein the processor in the host computer system is operable to execute the USB driver program.

30. The method of claim 18,

wherein the receiving of the data packet, the transmitting of the data packet, and the transmitting of the acknowledgement are performed by a USB Remote Root Hub, wherein the USB Remote Root Hub includes specialized logic to perform the receiving of the data packet, the transmitting of the data packet, and the transmitting of the acknowledgement.

31. The method of claim 18,

wherein the host controller and the first bus are substantially transparent to the USB Remote Root Hub.

32. The method of claim 18,

wherein the receiving of the data packet, the transmitting of the data packet, and the transmitting of the acknowledgement are performed by a USB Remote Root Hub, wherein the USB Remote Root Hub includes specialized logic to perform the receiving of the data packet, the transmitting of the data packet, and the transmitting of the acknowledgement;

and

wherein the host controller and the first bus are substantially transparent to the USB Remote Root Hub.

33. The method of claim 18, further comprising:

receiving a subsequent data packet from the USB device if the host acknowledgement is received from the host computer system before a time-out condition occurs.

34. The method of claim 18, further comprising:

re-sending the data packet to the host computer system one or more times if the host acknowledgement is not received from the host computer system before a time-out condition occurs.

35. The method of claim 34, further comprising:

executing an error routine if the host acknowledgement is not received from the host computer system after re-sending the data packet to the host computer system a maximum number of times.

36. The method of claim 18,

wherein the USB device comprises one of a display device, a pointing device, a keyboard, a disc drive, an optical drive, a printer, a fax machine, a scanner, or a tape drive.

37. The method of claim 18, wherein the first bus is a USBX bus.

38. A method for communicating data over a remote Universal Serial Bus (USB), the method comprising:

generating a data packet on the remote USB;

receiving the data packet from the remote USB;

transmitting the data packet to a host computer system over a first bus, wherein the first bus has a length greater than about 5 meters;

transmitting an acknowledgement (ACK) to a USB device over the USB, wherein said transmitting the ACK to the USB device occurs prior to a host acknowledgement being received from a host computer system acknowledging receipt of the data packet.

39. The method of claim 38,

wherein the generating the data packet on the remote USB is performed by the USB device.

40. The method of claim 38,

wherein the USB device comprises one of a monitor, a mouse, a keyboard, a disc drive, an optical drive, a laser printer, an ASCII printer, a fax machine, a scanner, or a tape drive.

41. The method of claim 38,

wherein the receiving the data packet from the remote USB is performed by a USB Remote Root Hub.

42. The method of claim 38,

wherein the transmitting the data packet to a host computer system over a first bus is performed by a USB Remote Root Hub.

43. The method of claim 38,

wherein the transmitting an acknowledgement (ACK) to the USB device over the USB is performed by a USB Remote Root Hub.

44. The method of claim 38, further comprising:

waiting for an acknowledgement from the host computer system, wherein the acknowledgement indicates that the data packet has been received by the host computer system;

if the acknowledgement has been received from the host computer system before a time-out condition occurs, then waiting for a next data packet from the USB device;

if the acknowledgement has not been received from the host computer system before the time-out condition occurs, then re-sending the data packet to the host computer system;

if the data packet has been re-sent to the host computer system a maximum number of times, then executing an error routine; and

if the data packet has not been re-sent to the host computer system a maximum number of times, then continuing the waiting for the acknowledgement from the host computer system.

45. The method of claim 44,

wherein the waiting for an acknowledgement from the host computer system is performed by a USB Remote Root Hub.

46. The method of claim 44,

wherein the waiting for a next data packet from the device is performed by a USB Remote Root Hub.

47. The method of claim 44,

wherein the re-sending the data packet to the host computer system is performed by a USB Remote Root Hub.

48. The method of claim 44,

wherein the executing an error routine is performed by a USB Remote Root Hub.

49. The method of claim 44,

wherein the continuing the waiting for the acknowledgement from the host computer system is performed by a USB Remote Root Hub.

50. The method of claim 44,

wherein the waiting for an acknowledgement, the waiting for a next data packet, the re-sending the data packet, the executing an error routine, and the continuing the waiting for the acknowledgement from the host computer system is performed by a USB Remote Root Hub.

51. The method of claim 38,

wherein the transmitting of the data packet to the host computer system comprises transmitting the data packet to a USB Extension (USBX) controller over a USBX bus, wherein the USBX controller is coupled to the host computer system, and wherein the USBX Controller and the USBX bus are operable to allow communication between the host computer system and a USB device over a distance which is greater than a maximum distance specified in a USB protocol specification.

52. The method of claim 51,

wherein the host computer system comprises the USBX Controller.

53. The method of claim 51,

wherein the host computer system comprises a processor and a memory, wherein the memory of the host computer system comprises a USB driver program, and wherein the processor in the host computer system is operable to execute the USB driver program.

54. The method of claim 53,

wherein the USBX controller and the first bus are substantially transparent to the USB driver program.

55. The method of claim 53,

wherein the USBX controller presents a USB compliant interface to the USB driver program.

56. The method of claim 51,

wherein the host computer system comprises a processor and a memory, wherein the memory of the host computer system comprises a USB driver program, and wherein the processor in the host computer system is operable to execute the USB driver program;

and

wherein the USBX controller presents a USB compliant interface to the USB driver program.

57. The method of claim 38,

wherein the first bus has a length greater than a maximum distance specified in a USB protocol specification.

58. The method of claim 38,

wherein the host computer system comprises a processor and a memory, wherein the memory of the host computer system comprises a USB driver program, and wherein the processor in the host computer system is operable to execute the USB driver program.

59. The method of claim 38,

wherein the receiving of the data packet, the transmitting of the data packet, and the transmitting of the acknowledgement are performed by a USB Remote Root Hub, wherein the USB Remote Root Hub includes specialized logic to perform the receiving of the data packet, the transmitting of the data packet, and the transmitting of the acknowledgement.

60. The method of claim 38, wherein the first bus is a USBX bus.

61. A system for communicating data over a Universal Serial Bus (USB), the system comprising:

a host computer system including a processor and a memory;

a host controller coupled to the host computer system;

a first bus which is coupled to the host controller;

a USB Remote Root Hub which is coupled to the first bus, wherein the USB Remote Root Hub is further coupled to the USB; and

at least one USB device, wherein the at least one USB device is coupled to the USB;

wherein the host controller, the first bus, and the USB Remote Root Hub are operable to allow communication between the host computer system and the USB device;

wherein the first bus has a length greater than about 5 meters.

62. The system of claim 61,

wherein the memory of the host computer system comprises a USB driver program, and wherein the processor in the host computer system is operable to execute the USB driver program; and

wherein the host controller presents a USB compliant interface to the USB driver program.

63. The system of claim 61, wherein the host controller and the first bus are substantially transparent to the USB driver program.

64. The system of claim 61, wherein the host controller and the first bus are substantially transparent to the USB Remote Root Hub.

65. The system of claim 61,

wherein the USB Remote Root Hub is operable to:

receive a data packet from the USB device through the USB bus;

transmit the data packet to the host computer system after receiving the data packet; and

send an acknowledgement (ACK) to the USB device after receiving the data packet;

wherein the host computer system is operable to transmit a host acknowledgement to the USB Remote Root Hub in response to the host computer system receiving the data packet transmitted from the USB Remote Root Hub;

wherein the USB Remote Root Hub is operable to send an acknowledgement (ACK) to the USB device prior to the USB Remote Root Hub receiving the host acknowledgement from the host computer system.

66. A system for communicating data over a Universal Serial Bus (USB), the system comprising:

a host computer system including a processor and a memory, wherein the memory of the host computer system comprises a USB driver program, and wherein the processor in the host computer system is operable to execute the USB driver program;

a host controller coupled to the host computer system;

a first bus which is coupled to the host controller;

a USB Remote Root Hub which is coupled to the first bus, wherein the USB Remote Root Hub is further coupled to the USB; and

at least one USB device, wherein the at least one USB device is coupled to the USB.

67. The system of claim 66,

wherein the host controller presents a USB compliant interface to the USB driver program.

68. The system of claim 66, wherein the host controller and the first bus are substantially transparent to the USB driver program.

69. The system of claim 66, wherein the host controller and the first bus are substantially transparent to the USB Remote Root Hub.

70. The system of claim 66,

wherein the USB Remote Root Hub is operable to:

receive a data packet from the USB device through the USB bus;

transmit the data packet to the host computer system after receiving the data packet; and

send an acknowledgement (ACK) to the USB device after receiving the data packet;

wherein the host computer system is operable to transmit a host acknowledgement to the USB Remote Root Hub in response to the host computer system receiving the data packet transmitted from the USB Remote Root Hub;

wherein the USB Remote Root Hub is operable to send an acknowledgement (ACK) to the USB device prior to the USB Remote Root Hub receiving the host acknowledgement from the host computer system.

71. A system for communicating data over a Universal Serial Bus (USB), the system comprising:

a host computer system including a processor and a memory;

a host controller coupled to the host computer system;

a first bus which is coupled to the host controller;

a USB Remote Root Hub which is coupled to the first bus, wherein the USB Remote Root Hub is further coupled to the USB; and

at least one USB device, wherein the at least one USB device is coupled to the USB;

wherein the USB Remote Root Hub is operable to;

receive a data packet from the USB device through the USB bus;

transmit the data packet to the host computer system after receiving the data packet; and

send an acknowledgement (ACK) to the USB device after receiving the data packet.

72. A method for communicating data over a remote Universal Serial Bus (USB), the method comprising:

receiving a data packet from a USB device through a USB bus;

transmitting the data packet to a host computer system over a first bus;

transmitting an acknowledgement (ACK) to the USB device over the USB bus, wherein said transmitting of the ACK to the USB device occurs prior to a host acknowledgement being received from the host computer system acknowledging receipt of the data packet;

wherein the receiving of the data packet, the transmitting of the data packet, and the transmitting of the acknowledgement are performed by a USB Remote Root Hub, wherein the USB Remote Root Hub includes specialized logic to perform the receiving of the data packet, the transmitting of the data packet, and the transmitting of the acknowledgement; and

wherein the host controller and the first bus are substantially transparent to the USB Remote Root Hub.