Interface apparatus

• US 20030115400A1
• Filed: 12/09/2002
• Published: 06/19/2003
• Est. Priority Date: 12/13/2001
• Status: Active Grant

• Current Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Original Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Inventors: Sugita, Hiroshi, Hoshino, Tsutomu, Kaneko, Tomokazu, Takahashi, Hirota, Edogawa, Kazuya, Sonobe, Kenichi
• Granted Patent: US 7,010,640 B2
• Time in Patent Office: Days
• US Class Current: 710/305
• CPC Class Codes: G06F 13/4081 Live connection to bus, e.g. hot-plugging current or voltage limitation during live insertion H02H9/004

Abstract

In a CPU, a FET is turned off and power is not supplied to a power supply element of a transceiver for a period of time until predetermined initialization processing, which is implemented in a peripheral device when power is supplied via a cable from a host PC, has been concluded (i.e., a period of time until it becomes possible for the peripheral device to initiate data communication with the host PC). Thus, even if the peripheral device and the host PC are physically connected by a cable, data signals transmitted along signal lines are not relayed by the transceiver to a logic controller, whereby it in effect becomes possible to set the peripheral device in a pseudo-non-connected state with respect to the host PC.

Claims

1. An interface apparatus for mediating the sending/receiving of signals between a plurality of devices that are mutually connected by a signal line having at least one pair of signal transmission lines, the interface apparatus comprising:

a signal relay section for relaying electric signals that are transferred via the signal line between the devices;

a connection determination section for determining, on the basis of signal voltage in each signal transmission line of the signal line, whether or not the devices are connected; and

a connection control section for incapacitating, when it has been determined by the connection determination section that the devices are connected, the signal relay section until the devices move to a state in which it is possible to mutually send/receive the signals.

4. The interface apparatus of claim 1, wherein each of the signal relay section, the connection determination section and the connection control section has a specification that conforms to the USB standard.

7. The interface apparatus of claim 1, wherein the signal line comprises a USB cable.

10. The interface apparatus of claim 1, wherein the devices include a host PC and at least one peripheral device, the at least one peripheral device conducting initialization processing immediately after power has been supplied thereto, with the peripheral device being unable to send signals to or receive signals from the host PC for a predetermined period of time until the initialization processing has been concluded.

13. The interface apparatus of claim 1, wherein the interface apparatus is disposed in one of the devices.

16. The interface apparatus of claim 1, wherein the devices include a host PC and a peripheral device for sending signals to and receiving signals from the host PC, with the interface apparatus being disposed in the peripheral device.

2. An interface apparatus for mediating the sending/receiving of signals between a plurality of devices that are mutually connected by a signal line having at least one pair of signal transmission lines, the interface apparatus comprising:

a signal relay section for relaying electric signals that are transferred via the signal line between the devices;

a connection determination section for determining, on the basis of signal voltage in each signal transmission line of the signal line, whether or not the devices are connected; and

a connection control section for stopping, when it has been determined by the connection determination section that the devices are connected, power supply to the signal relay section until the devices move to a state in which it is possible to mutually send/receive the signals.

5. The interface apparatus of claim 2, wherein each of the signal relay section, the connection determination section and the connection control section has a specification that conforms to the USB standard.

8. The interface apparatus of claim 2, wherein the signal line comprises a USB cable.

11. The interface apparatus of claim 2, wherein the devices include a host PC and at least one peripheral device, the at least one peripheral device conducting initialization processing immediately after power has been supplied, with the peripheral device being unable to send signals to or receive signals from the host PC for a predetermined period of time until the initialization processing has been concluded.

14. The interface apparatus of claim 2, wherein the interface apparatus is disposed in one of the devices.

17. The interface apparatus of claim 2, wherein the devices include a host PC and a peripheral device for sending signals to and receiving signals from the host PC, with the interface apparatus being disposed in the peripheral device.

3. An interface apparatus for mediating the sending/receiving of signals between a plurality of devices that are mutually connected by a signal line having at least one pair of signal transmission lines, the interface apparatus comprising:

a signal relay section for relaying, when a differential voltage is within a predetermined value range, electric signals that are transferred via the signal line between the devices, the differential voltage value being a difference in respective signal voltages in the pair of signal transmission lines;

a connection determination section for determining, on the basis of the signal voltage in each signal transmission line of the signal line, whether or not the devices are connected; and

a connection control section for setting, when it has been determined by the connection determination section that the devices are connected, the differential voltage in each signal transmission line of the signal line to be outside the predetermined value range until the devices move to a state in which it is possible to mutually send/receive the signals.

6. The interface apparatus of claim 3, wherein each of the signal relay section, the connection determination section and the connection control section has a specification that conforms to the USB standard.

9. The interface apparatus of claim 3, wherein the signal line comprises a USB cable.

12. The interface apparatus of claim 3, wherein the devices include a host PC and at least one peripheral device, the at least one peripheral device conducting initialization processing immediately after power has been supplied thereto, with the peripheral device being unable to send signals to or receive signals from the host PC for a predetermined period of time until the initialization processing has been concluded.

15. The interface apparatus of claim 3, wherein the interface apparatus is disposed in one of the devices.

18. The interface apparatus of claim 3, wherein the devices include a host PC and a peripheral device for sending signals to and receiving signals from the host PC, with the interface apparatus being disposed in the peripheral device.