Patent Publication Number: US-2002010816-A1

Title: Computer peripheral switching device

Description:
FIELD OF THE INVENTION  
       [0001] The present invention is related to computer input devices and in particular to an input device that controls switching circuitry for computer peripherals.  
       BACKGROUND OF THE INVENTION  
       [0002] In an environment such as a network server control room, a computer user needs to control multiple computers. Each computer is usually equipped with a monitor and input devices such as a keyboard and a pointing device. However, the duplication of monitors and input devices among the computers is costly in terms of money and space. In an effort to reduce these costs, manufacturers have devised switching circuitry which switches the connections of a single monitor, a single keyboard, and/or a single pointing device among a number of computers. The switching operations are controlled through buttons or knobs built into a box containing the circuitry. The size of the box depends on the number of computers connected to the switch since the amount of switching circuitry increases proportionally as the number of computers increases.  
       [0003] Thus in order to switch the monitor, keyboard, and/or pointing device from one computer to another, the user must either move to where the switch box is located or place the switch box near his/her desk. Either solution is unsatisfactory. The first option means the user cannot quickly switch among many computers and the second option takes up premium space on or near the user&#39;s desktop.  
       [0004] One solution to the above problem is presented by switch boxes which are controlled using a key sequence input by the user at the keyboard. The switch box intercepts the scan code generated by the key sequence and switches the selected peripherals to the next computer in sequence. One family of such switch boxes are the ServSwitches from Black Box Inc. However, the user must remember the precise key sequence and must ensure that the sequence is not used by any software packages that execute on the computers controlled by the switch box.  
       [0005] There is a need for a switching device that allows control of multiple computers from a single location convenient to the user, does not interfere with software running on the computers, and which does not take up valuable space near the user.  
       SUMMARY OF THE INVENTION  
       [0006] A pointing device, such as a mouse, trackball, or graphics tablet, incorporates a selection switch, such as a button, that signals switching circuitry external to the pointing device to switch the connections of input devices, such as the pointing device and a keyboard, from one computer to another. Optionally, the selection switch also switches an additional peripheral, such as a computer monitor, between computers.  
       [0007] The switching circuitry is coupled to the pointing device and has at least two ports for coupling to computers. The selection switch is also coupled to the switching circuitry. Activating the selection switch signals the switching circuitry to couple the input devices to a selected one of the ports and thus to one of the computers. The additional peripheral is also coupled to the switching circuitry so that it is coupled to the selected one of the ports when the selection switch is activated.  
       [0008] The selection switch signals the switching circuitry through an additional line in a cable that couples the pointing device to the switching circuitry, or through an electromagnetic signal generated when the selection switch is activated.  
       [0009] The selection switch also includes a mechanism to prevent its inadvertent activation.  
       [0010] Additionally, the pointing device and another input device, such as a keyboard, each incorporate a selection switch and activating either selection switch signals the switching circuitry to switch both input devices and any additional peripheral to a different port.  
       [0011] Because the selection switch and the switching circuitry are physically separate and because the selection switch is incorporated into a pointing device already existing on the user&#39;s desktop, the present invention overcomes the limitations of the prior art by permitting the user to switch input devices and a peripheral among computers from a single location without taking up additional desk space and without potential interference with software executing on the computers. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0012]FIG. 1 is a block diagram of one embodiment of a computer peripheral switching device in which the pointing device is a mouse.  
     [0013]FIG. 2 is a block diagram of an alternate embodiment of the embodiment of FIG. 1 showing a different location for a control button on the mouse.  
     [0014]FIG. 3 is a block diagram showing both a mouse and a keyboard controlling computer peripheral switching circuitry.  
     [0015]FIG. 4 is a block diagram of an alternate embodiment of FIG. 3 which also controls connections for a computer monitor.  
     [0016]FIG. 5 is a block diagram of an alternate embodiment of the computer peripheral switching device in which the pointing device is remotely coupled to the switch box.  
     [0017]FIG. 6 is a block diagram of an alternate embodiment of the computer peripheral switching device in which a microprocessor is coupled between the pointing device and the switching circuitry.  
     [0018]FIG. 7 is a field layout diagram for a data packet sent by one embodiment of the computer peripheral switching device to the switching circuitry. 
    
    
     DESCRIPTION OF THE EMBODIMENTS  
     [0019] In the following detailed description of the embodiments, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural, logical and electrical changes may be made without departing from the spirit and scope of the present inventions. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present inventions is defined only by the appended claims.  
     [0020] The leading digits of reference numbers appearing in the Figures corresponds to the Figure number, with the exception that the same reference number is used throughout to refer to an identical component which appears in multiple Figures. Signals and connections may be referred to by the same reference number or label, and the actual meaning will be clear from its use in the context of the description.  
     [0021]FIG. 1 is a block diagram of one embodiment of a computer peripheral switching device  100  in which a pointing device  101  is represented generically as a mouse. Switching circuitry  105  is coupled to the mouse  101  through a cable  120  containing industry standard signal lines  121  for a serial pointing device. The switching circuitry  105  in the embodiment shown in FIG. 1 comprises four serial ports  107 - 110  which are in turn coupled to serial ports on four computer systems (not shown). Alternate embodiments in which the switching circuitry switches a single input device among more or fewer than four computer systems will be apparent to those skilled in the art as will embodiments incorporating non-serial protocols. Commonly available switching circuitry has the capability to switch one device among multiple ports as required by the invention and is therefore not described further herein. Some circuits incorporate manually rotated switches. In such devices, an actuator is provided which rotates the switch in response to selected signals. One example of readily available switching circuitry can be found in Black Box Inc.&#39;s SW623A product.  
     [0022] A selection switch  103  is located on a side of the mouse  101  where it is convenient to the user. The selection switch  103  is coupled to the switching circuitry  105  through an additional signal line  123  integrated into the cable  120 . When the user activates the selection switch  103 , a signal is sent to the switching circuit to cause it to couple the serial lines  121  in the cable  120  to the serial ports  107 - 110 , thus completing a connection between the mouse  101  and the computer system coupled to the selected port.  
     [0023] In the embodiment illustrated in FIG. 1, the selection switch  103  is a push button manufactured into the side of the mouse case. Pressing on the push button sends the signal to the switching circuitry to couple the mouse  101  to one of the ports  107 - 110 . Each time the push button is pressed, a different one of the ports  107 - 110  is coupled to the mouse  101  so that the user can rotate the use of the mouse  101  among the computers coupled to ports  107 - 110 . Alternately, the push button shown in FIG. 1 is replaced by a sliding button in which each different position of the sliding button corresponds to one of the ports  107 - 110 . In a further alternate embodiment, a wheel is used in place of the push button. In yet another embodiment, two selection switches are incorporated into the pointing device; pressing one of the selection switches moves forward through the sequence of computers while pressing the other moves backwards through the sequence.  
     [0024] In addition, the location of the selection switch  103  is not limited to the side of the mouse  101 . One alternate embodiment in which the selection switch  103  is placed between standard command buttons on top of a mouse  102  is shown in FIG. 2. In the alternate embodiment illustrated in FIG. 2, the selection switch  103  can any of the mechanisms described above. Furthermore, when the selection switch  103  is located on top of the mouse  102 , the selection switch  103  can operate similarly to a joystick (or a miniature pointing stick) in which the user rotates the selection switch  103  through a 360° circle. Positions on the circle correspond to the ports  107 - 110 . Further alternate embodiments for associating the position of the selection switch  103  with the ports  107 - 110  will be apparent to those skilled in the art.  
     [0025] Inadvertent activation of the selection switch  103  can be prevented by increasing the resistance of a contact mechanism, such as using a spring with a high spring constant, attached to the selection switch  103  such that more than casual force is needed to activate the selection switch  103 . Such a contact mechanism is applicable to both the push button and the slide switch embodiments. Other commonly available mechanisms which are less susceptible to inadvertent activation than toggle-like push buttons are suitable for use as the selection switch  103  as will be apparent to those skilled in the art. Requiring a combination of movements, such as pushing in the selection switch  103  while simultaneously moving it to a different position, defines still another alternate embodiment that prevents inadvertent activation.  
     [0026] In another aspect of the invention shown in FIG. 6, activating the selection switch  103  sends a serial data packet on the standard serial lines  121  in the cable  620  to the switching circuitry  105 . A microprocessor  601 , such as a Hitachi H 8  controller, coupled to the switching circuitry  105 , recognizes the data packet as a signal to connect the serial lines  121  from the pointing device  101  to one of the ports  107 - 110  and thus to the serial port of one of the computers. In this embodiment, the additional signal line  123  shown in FIG. 1 is unnecessary. Alternatively, in a further embodiment not illustrated, the serial data packet is passed through the switching circuitry  105  to the selected computer. A device driver active in the currently selected computer processes the data packet and signals the switching circuitry  105  to switch the input device  101  to another one of the ports  107 - 110 . The microprocessor  601  is not necessary because the central processing unit of the selected computer processes the data packet instead. An example data packet  700 , illustrated in FIG. 7, contains a packet identifier  701  to distinguish it as a switching control packet and a port identifier  703  which designates which port  107 - 110  is to be coupled to the input device  101 . In a further embodiment not illustrated, the port identifier  703  is sent as part of a standard input device data packet such as used to signal cursor movements and button states to the microprocessor  601  as is well known in the art.  
     [0027] The device driver or equivalent software running in the computer systems coupled to the ports  107 - 110 , such as Plug-n-Play® software included in Windows  95 ®, permits the disconnection and re-connection of input devices without rebooting the computers. Alternatively, for systems which do not incorporate such software, the switching circuitry  105  transmits signals to the non-selected computer systems to emulate a connected but inactive input device. As both methods of enabling input devices to be connected and disconnected without rebooting a computer are well-known in the art, they are not illustrated or described further herein.  
     [0028] The invention is not limited to control from a single device. FIG. 3 is a block diagram of an alternate embodiment of the computer peripheral switching device in which the mouse  101  of FIG. 1 and a keyboard  301  both control the switching circuitry. The keyboard  301  is a specially-manufactured keyboard with a key  303  acting as the selection switch. Activating either the button  103  on the mouse or the key  303  on the keyboard signals the switching circuitry  105  to switch both the mouse  101  and the keyboard  301  to one of the ports  107 - 110 .  
     [0029] Furthermore, in an additional embodiment shown in FIG. 4, a peripheral  401 , illustrated generically as a computer monitor, is coupled to the switching circuitry  105  so that the peripheral is also switched to the selected computer when the mouse  101  and the keyboard  301  are switched. The switching of peripherals other than a computer monitor as shown in FIG. 4 will be readily apparent to one skilled in the art.  
     [0030]FIG. 5 illustrates yet another alternate embodiment of the invention in which the pointing device  501 , again shown as a mouse, is not physically connected to the switching circuitry  105 , but instead is coupled through the use of an electromagnetic signal  515  generated by an emitter  517  positioned within the pointing device  501 . The emitter is coupled to the selection switch  503  so that when the selection switch  503  is activated the signal  515  is transmitted. A receiver  513 , coupled to the switching circuitry  105 , receives the signal  515  and routes it to the switching circuitry  105 . The signal  515  can correspond to the signal sent through the additional signal line  123  (FIG. 1), or multiple signals  515  can form a serial data packet  700  (FIG. 7) for processing by a microprocessor  601  (FIG. 6) or by the currently selected computer as explained above. Electromagnetic receivers and emitters with the necessary capabilities, such as model numbers BPV22BF (receiver) and TS1P5201 (emitter) from Telefunken of Germany that work in the infrared portion of the electromagnetic spectrum, and radio frequency transceiver A5980800/R567121 from Mitsumi Japan, are standard off-the-shelf components in the industry and are not discussed further.  
     [0031] It is to be understood that the above description is intended to be illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. For example, multiple and different types of switching circuitry are capable of switching between devices can be used. The only required functionality of such circuitry is that it is capable of accepting signals and switching in response to the signals. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.