Automated selection between a USB and PS/2 interface for connecting a keyboard to a computer

• US 6,725,318 B1
• Filed: 02/29/2000
• Issued: 04/20/2004
• Est. Priority Date: 02/29/2000
• Status: Expired due to Term

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Mullins, Keith, Sherman, Nathan C.
• Primary Examiner(s): Gaffin, Jeffrey
• Assistant Examiner(s): Farooq, Mohammad O.
• Application Number:
  US09/515,563
• Time in Patent Office: 1,512 Days
• Field of Search: 710/2, 710/7, 710/8, 710/36, 710/62, 710/63, 710/67, 710/304, 710/313
• US Class Current: 710/313
• CPC Class Codes: G06F 3/0202 Constructional details or processes of manufacture of the input device

Abstract

A keyboard selectively operable to convey data to and from a host or personal computer (PC) through a universal serial bus (USB) port and/or a personal system/2 (PS/2) port. The keyboard is preferably connected to both the USB port and PS/2 port on the host or PC, if available. Preference is given to communicating data from the keyboard to the host or PC through the PS/2 port. However, if the PS/2 port is unavailable, not connected, or inoperative, the keyboard data are communicated to the host or PC through the USB port (assuming that it is available, operative, and connected). As soon as the PS/2 port on the host or PC is again connected to the keyboard, such data will again be communicated through the PS/2 port. In addition, the keyboard includes auxiliary USB ports to which USB-capable peripheral devices can be connected. USB data can then be communicated between the PC and the USB-capable peripheral devices via the keyboard and its connection to the USB port on the host or PC. Power supplied from the PS/2 port on the host or PC is monitored to determine whether that port is connected to the keyboard, and in response, to cause data arising from the user actuating keys on the keyboard to be supplied to the host or PC through the PS/2 port.

Claims

1. An external user input device adapted to selectively couple and communicate user input data through at least one of a universal serial bus (USB) port and an alternative port of a host computing device, comprising:

(a) at least one data switch capable of being activated by a user to determine data that are transmitted to a host computing device;

(b) a power sense circuit that determines whether electrical power is being supplied to the external user input device from an alternative port of a host computing device and produces a signal indicative thereof; and

(c) a state switch, coupled to the power sense circuit and said at least one data switch, to receive the signal produced thereby, and in response upon detecting a change in state to said signal indicating that an alternative port is supplying the electrical power indicative thereof, enabling the host computing device to receive data transmitted from said at least one data switch through an alternative port, and otherwise enabling the host computing device to receive data transmitted from said at least one data switch through a USB port.

2. The external user input device of claim 1, further comprising a USB hub circuit having at least one auxiliary USB port adapted to connect to a USB peripheral device, said USB hub circuit enabling transfer of data between an external USB peripheral device and the USB port of the host computing device.

3. The external user input device of claim 1, wherein the alternative port comprises a personal system/2 (PS/2) port.

4. The external user input device of claim 1, wherein said at least one data switch comprises a plurality of alphanumeric keys.

5. The external user input device of claim 1, further comprising signal conditioning circuitry that conditions data signals and power signals.

6. The external user input device of claim 1, wherein an alternative port has priority over a USB port of a host computing device, so that the state switch will preferably employ an alternative port of a host computing device for exchanging data, if the signal produced by the power sense circuit indicates that an alternative port is providing electrical current to the external user input device.

7. The external user input device of claim 6, wherein if a host computing device has been receiving data transmitted from said at least one data switch through a USB port, upon detecting a change in state in which electrical power has now available from an alternative port of a host computing device, the signal produced by the power sense circuit changes, causing the state switch to stop a host computing device from receiving the data from said at least one data switch through a USB port, and instead enabling the host computing device to receive said data through an alternative port of the host computing device.

8. The internal user input device of claim 6, wherein if a host computing device has been receiving data transmitted from said at least one data switch through an alternative port, upon detecting a change in state in which electrical power is no longer supplied to the external user input device from an alternative port of a host computing device, the signal produced by the power sense circuit changes, causing the state switch to stop a host computing device from receiving the data from said at least one data switch through an alternative port, and instead enabling a host computing device to receive said data through a USB port.

9. The external user input device of claim 6, further comprising a data format circuit coupled to said at least one data switch and to the state switch, said data format circuit formatting the data determined by said at least one data switch for input to an alternative port of a host computing device if the state switch has enabled the data to be transmitted to an alternative port of a host computing device, and otherwise, formatting said data for input to a USB port of a host computing device.

10. The external user input device of claim 9, further comprising at lease one cable coupled to the data format circuit, and including:

(a) a USB port connector adapted to connect to a USB port on a host computing device; and

(b) an alternative port connector adapted to couple to an alternative port on a host computing device.

11. An external keyboard adapted to couple to a universal serial bus (USB) port on a host computing device, if available, and to a personal system/2 (PS/2) port on the host computing device, if available, comprising:

(a) a plurality of data switches that produce data signals when actuated by a user;

(b) a keyboard circuit that is coupled to the plurality of data switches to receive the data signals, said keyboard circuit being adapted to selectively format the data signals in a USB format and in a PS/2 format;

(c) a power sense circuit that determines whether the external keyboard is coupled to a PS/2 port of a host computing device by sensing an electrical potential supplied from a PS/2 port of a host computing device if the external keyboard is coupled thereto, said power sense circuit produces a signal indicative of whether said electrical potential has been sensed;

(d) a data source switch that is coupled to the external keyboard circuit and to the signal produced by the power sense circuit, said data source switch selectively determining whether the data signals formatted in the USB format and in the PS/2 format are respectively coupled to a USB port and a PS/2 port on a host computing device, as a function of the signal produced by the power sense circuit; and

(e) a hub circuit having an auxiliary port adapted to connect to an external peripheral device, said hub circuit enabling transfer of data between an external peripheral device and the host computing device.

12. The external keyboard of claim 11, wherein the data source switch preferentially selects the data signals in the PS/2 format for input to a PS/2 port on a host computing device if the signal produced by the power sense circuit indicates that the electrical potential is being supplied from a PS/2 port of a host computing device.

13. The external keyboard of claim 11, wherein the data source switch blocks the data signals in the USB format for input to a USB port on a host computing device if the signal produced by the power sense circuit indicates that the electrical potential is being supplied from a PS/2 port of a host computing device.

14. The external keyboard of claim 11, wherein the hub circuit comprises a USB hub circuit that includes a plurality of USB ports, including one USB port that is coupled to the external keyboard circuit to receive the data signals in the USB format, said USB hub circuit being coupled to a USB port of a host computing device, if available, to transfer USB formatted data between the USB hub circuit and a host computing device, the auxiliary port of the hub circuit comprising a USB ports adapted to couple to a USB peripheral device.

15. The external keyboard of claim 11, further comprising conditioning circuitry that conditions electrical current signals and data signals within the external keyboard.

16. The external keyboard of claim 11, further comprising a voltage regulator that regulates an electrical current received from a USB port on a host computing device.

17. The external keyboard of claim 11, further comprising at least one cable coupled to the data format circuit and to:

(a) a USB port connector adapted to connect to a USB port on a host computing device; and

(b) a PS/2 port connector adapted to couple to a PS/2 port on a host computing device.

18. A method for enabling an external user input device to be selectively coupled to communicate data signals produced as a result of user interaction with the external user input device, with either a USB port on a host computing device or an alternative port on the host computing device, comprising the steps of:

(a) providing an external user input device capable of automatically coupling to a host computing device using either of two ports provided on the external user input device, said two ports including the USB port and the alternative port;

(b) sensing whether a preferred one of the USB port and the alternative port is coupled in communication with the external device user input device; and

(c) if the preferred one of the USB port and the alternative port on the host computing device is coupled to the external user input device, enabling communication of the data signals between the external user input device and said preferred one of the USB port and the alternative port on a host computing device.

19. The method of claim 18, wherein the step of sensing comprises the steps of detecting a voltage provided by the preferred one of a USB port and an alternative port of a host computing device to the external user input device, and if the voltage is detected enabling the data signals produced by the external user input device to be communicated to a host computing device only through said preferred one of a USB port and an alternative port.

20. The method of claim 18, further comprising the step of providing a plurality of auxiliary USB ports on the external user input device for communicating data in a USB format between at least one USB peripheral device that is connected to one of the plurality of USB ports, and a host computing device.

21. The method of claim 20, further comprising the step of enabling communication of the data between said at least one USB peripheral device and an auxiliary USB port of the hub computing device, even if the data from the external user input device is preferably communicated to an alternative port of a host computing device.

22. The method of claim 18, wherein the preferred one of a USB port and an alternative port of a hub is an alternative port, further comprising the step of disabling the transfer of the data produced as a result of the user interaction with the external user input device to a USB port if an alternative port of a host computing device is coupled in communication with the external user input device, so that said data are communicated only through an alternative port.

23. The method of claim 18, wherein the external user input device comprises a keyboard.

24. The method of claim 18, wherein an alternative port is a personal system/2 (PS/2) port.

25. A external device adapted to selectively couple and communicate data through at least one of a Universal Serial Bus (USB) port and an alternative port of a host computing device, said external device receiving electrical power from the host computing device through at least one of a USB port and an alternative port of the host computing device, comprising:

(a) at least one of a data switch capable of being activated by a user to determine data that are transmitted to a host computing device, and an indicator that indicates a condition of the external device; and

(b) circuit means for determining whether electrical power is being supplied to the external device from an alternative port of a host computing device, and for enabling external device data to be transferred through;

(i) an alternative port of a host computing device in response to determining that an alternative port is supplying electrical power to the external device; and

(ii) a USB port of a host computing device in response to determining that an alternative port is not supplying electrical power to the external device.

26. The device of claim 25, wherein the circuit means includes a pull up resistor that is disabled by application of electrical power to the device from an alternative port of a host computing device, disablement of the pull up resistor preventing device data from being transferred through a USB port of a host computing device.

27. An external user input device adapted to selectively couple and communicate user input data through at least one of a universal serial bus (USB) port and an alternative port of a host computing device, comprising:

(a) a USB connector adapted to couple to a USB port of a host computing device and to selectively transmit data thereby;

(b) an alternative connector adapted to couple to an alternative port of a host computing device and to selectively transmit data thereby;

(c) at least one data input element, which when activated by a user, produces user input data for transmission to a host computer device;

(d) a power sense circuit coupled to said alternative connector, said power sense circuit determining whether electrical power is being supplied to said external user input device from an alternative port of a host computing device to which said alternative connector is coupled, said power sense circuit producing a signal indicative thereof; and

(e) a state switch coupled to said power sense circuit and to said at least one data input element such that said state switch receives said signal produced by said power sense circuit, and in response to said signal, selects one of said USB connector and said alternative connector that said external user input device will employ to transmit said user input data to a host computer device, when said external user input device is coupled to a host computing device using one of said USB connector and said alternative connector.

28. The external user input device of claim 27, wherein said external user input device further comprises at least one input USB port adapted to connect to a USB peripheral device, each input USB port being coupled to said USB connector to form a USB hub circuit, such that peripheral device data from a USB peripheral device connected to any input USB port will be transmitted to a host computing device when said USB connector is coupled to a USB port of that host computing device.

29. The external user input device of claim 27, wherein the alternative connector comprises a personal system/2 (PS/2) connector adapted to couple to a PS/2 port of a host computing device.

30. The external user input device of claim 27, wherein said at least one data input element comprises a plurality of alphanumeric keys.

31. The external user input device of claim 27, wherein when said signal produced by said power sense circuit indicates that electrical power is being supplied to said external user input device from an alternative port of a host computing device to which said alternative connector is coupled, said state switch selects said alternative connector to transmit said external user input data to a host computing device.

32. An external keyboard adapted to couple to one of a universal serial bus (USB) port and a personal system/2 (PS/2) port on a host computing device, comprising:

(a) a USB connector adapted to couple to a USB port of a host computing device and to selectively transmit data to the-host computing device thereby;

(b) a PS/2 connector adapted to couple to a PS/2 port of a host computing device and to selectively transmit data to the host computing device thereby;

(c) a plurality of data switches that produce data signals when actuated by a user;

(d) a keyboard circuit that is coupled to the plurality of data switches to receive the data signals, said keyboard circuit being adapted to selectively format the data signals in a USB format and in a PS/2 format;

(e) a power sense circuit that determines whether the external keyboard is coupled to a PS/2 port of a host computing device by sensing an electrical potential supplied from a PS/2 port of a host computing device if the external keyboard is coupled thereto, said power sense circuit producing a signal indicative of whether said electrical potential has been sensed; and

(f) a data source switch that is coupled to the external keyboard circuit to receive the signal produced by the power sense circuit, said data source switch selectively determining whether the data signals formatted in the USB format or in the PS/2 format are transmitted to the host computing device using a corresponding one of the USB connector and the PS/2 connector, as a function of the signal produced by the power sense circuit.

33. A method for enabling a external user input device that includes both a USB connector adapted to couple to a USB port of a host computing device and an alternative data connector adapted to couple to an alternative data port of a host computing device, to selectively determine which of the USB connector and the alternative data connector to utilize to transmit user input data to a host computing device, comprising the steps of:

(a) determining if the alternative data connector is coupled in communication with an alternative data port of a host computing device; and

(b) if the alternative data connector is coupled in communication with an alternative data port of a host computing device, enabling communication of the user input data between the external user input device and the host computing device using the alternative data connector, and otherwise, enabling communication of the user input data between the external user input device and the host computing device using the USB connector.

34. The method of claim 33, wherein the step of determining comprises the step of detecting a voltage provided by a host computing device to the alternative data connector.

35. The method of claim 33, further comprising the step of providing a plurality of auxiliary USB ports on the external user input device for communicating peripheral device data in a USB format to a host computing device using the USB connector, when at least one USB peripheral device is connected to one of the plurality of auxiliary USB ports, and the USB connector is coupled to a USB port of a host computing device.

36. The method of claim 33, further comprising the step of providing a hub circuit having an auxiliary Port adapted to connect to an external peripheral device for enabling transfer of data between an external peripheral device and the host computing device.