Interactive video distribution systems – Video distribution system with upstream communication – Transmission network
Reexamination Certificate
1998-05-05
2003-04-29
Kelley, Chris (Department: 2611)
Interactive video distribution systems
Video distribution system with upstream communication
Transmission network
C713S300000, C713S340000, C345S168000, C710S072000
Reexamination Certificate
active
06557170
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to keyboard, video and mouse switches, commonly known as KVM switches, wherein at least one workstation is coupled to the KVM switch for operation of the switch, the workstation also connectable via the KVM switch to one of a plurality of computers, and particularly to such a KVM switch incorporating power control means so that an operator at the workstation may control electrical power to each of the computers.
BACKGROUND OF THE INVENTION
Conventionally, and referring to
FIG. 1
, prior art keyboard, video, and mouse (KVM) switching units, as illustrated by KVM unit
10
, allow signals from a workstation or console
26
generally comprising a keyboard
12
, mouse or other digital pointing device
14
and video signals to monitor
16
to be selectively coupled to/from a plurality of computers
18
,
20
,
22
, and
24
. These KVM switches
10
are conventionally provided with a plurality of computer interface ports so that a plurality of computer keyboard, video and mouse connections may be made to the KVM switch. As such, and by way of the example, shown in
FIGS. 1
up to
4
keyboard, video and mouse connections from respective computers may be made to a single KVM switching unit
10
. This allows a user at therefor console
26
to operate and display video from any one of computers
18
-
24
via KVM unit
10
. Computers
18
,
20
,
22
,
24
are typically file servers or used in applications not requiring continuous connection to keyboards, mice, and monitors. KVM unit
10
may be provided with an OSD (ON SCREEN DISPLAY) user interface
27
, which provides convenient visual means, such as a selection of pop-up or pull-down menus, by which the user may operate KVM unit
10
. KVM switching circuitry
28
is used to control routing of keyboard, mouse and video signals between the selected one of computers
18
,
20
,
22
,
24
and console
26
.
Most, if not all, of the KVM units marketed today contain at least one KVM channel microprocessor
30
that routes keyboard and mouse data and clock signals to a selected one of computers
18
,
20
,
22
,
24
, and a main microprocessor
32
that controls operation of KVM unit
10
. The KVM channel microprocessors
30
each control a video switch (not shown in
FIG. 1
) to connect or disconnect a selected or deselected computer's video signals to/from an internal video bus that carries video signals from computers
18
,
20
,
22
,
24
to monitor
16
. Commands from main microprocessor
32
instruct channel microprocessors
30
as to when to activate or deactivate the video switch. Further, channel microprocessors
30
route data from computers
18
,
20
,
22
, and
24
to main microprocessor
32
.
Main microprocessor
32
passes keyboard and mouse signals from the selected one of computers
18
,
20
,
22
,
24
to ON SCREEN DISPLAY interface
27
, which serves as an interface for the user, typically by presenting the user with a series of menu screens from which to conveniently select from a variety of menu options that operate KVM unit
10
. As stated, the OSD interface allows the user to view a variety of menu selections whenever he wishes to perform a switch, power control, or administrative function. In the case where the user is a supervisor, such as a system administrator, OSD interface
27
may be used to perform administrative functions such as assigning passwords and security levels to individual users. OSD user interface
27
is provided with an OSD main microprocessor
34
, which is coupled to pass commands between keyboard
12
, mouse
14
and KVM switch
28
. Commands and responses passed on mouse and keyboard lines from keyboard
12
and mouse
14
allow OSD main microprocessor
34
to control the functions of KVM switch
28
and monitor its status. Video from KVM switch
28
passes through an OSD video circuit
36
which is controlled by an OSD video microprocessor
38
which is in turn controlled by OSD main microprocessor
34
. OSD video circuit
36
normally passes video signals from KVM switch
28
to console video monitor
16
. Upon activation of a menu, OSD video circuit
36
injects video signals which superimpose a menu or menus onto the video signals provided by KVM switch
28
. OSD main microprocessor
34
is provided with program memory for storage of the interface program and menus required for operation of OSD main microprocessor
34
, read/write memory (RAM), such as buffer memory for temporary storage of data, and non-volatile memory for permanent or semi-permanent storage of data such as the user's preferences for “hotkey” sequences used to activate the KVM switch features and user names and passwords. Commands are received by OSD video microprocessor
38
from OSD main microprocessor
34
, causing OSD video circuit
36
to activate or deactivate. Console keyboard
12
is used to enter data or selections presented by the pop-up menus. When the user is not a performing a switching, or administrative function the console video monitor and the console keyboard are used as a normal video monitor and keyboard attached to KVM switch
28
.
The keyboard and mouse data and clock signals from console keyboard
12
and mouse
14
are received by OSD main microprocessor
34
and normally passed to KVM switch
28
. Signals from computers
18
-
24
are normally passed via KVM switch
28
to console keyboard
12
and mouse
14
. With respect to “hot-key” sequences, OSD main microprocessor
34
responds by commanding OSD video microprocessor
38
to activate a pop-up menu. Concurrently, keyboard and mouse data and clock signals from console keyboard
12
and mouse
14
are prevented from being passed to KVM switch
28
while the pop-up menu is active. Rather, any keyboard or mouse commands applied to OSD main microprocessor
34
are used to change the pop-up menu content or set configuration data according to the keyboard and/or mouse entries by the user.
In some devices of the prior art, AC power from a conventional power source is simply applied to computers
18
,
20
,
22
, and
24
from a power distribution unit
40
, as shown in FIG.
1
. In other prior art devices, as shown in
FIG. 2
, a power switch
42
is conventionally coupled to AC power and to an ASCII terminal
44
coupled to a microprocessor
46
inside power switch
42
. Microprocessor
46
in turn is coupled to energize or deenergize, through appropriate drivers, relays or solid state power switching devices
48
,
50
,
52
, and
54
, which in turn couples or decouples AC power to computers
18
,
20
,
22
, and
24
. Some applications of this type power control system provide a means for individually switching ON or OFF the AC power to computers
18
-
24
from a remote location, and to implement security options such as password protection.
Some of the drawbacks of these computerized power switches are that the ASCII terminal that controls the power switch is separate from the console controlling the KVM switch, meaning that space must be made available for both the console and the ASCII terminal. Also, the menu options or other control scheme of the OSD interface is invariably different from the menu selections of the computerized power switch. This requires the operator to be familiar with two computerized control schemes instead of one, which is inconvenient and may lead to errors in operation of the systems. Further, two separate computerized systems requires that passwords and other security protocols and data bases be duplicated.
With respect to power control switches that are not under microprocessor control, these power switches must be operated manually, which is inconvenient if the power switch is remotely located from the console
12
operating KVM unit
10
. Also, power status of these manually operated switches cannot be checked from a central location. Further, since there are no security provisions in these manually operated switches, they may be operated by anyone.
In view of the foregoing, it is one object of the invention to provide a KVM switch having integrat
Brown Steven F.
Reed Douglas D.
Shatas Remigus G.
Wilder David E.
Brown Reuben M.
Cybex Computer Products Corp.
Kelley Chris
Nixon & Vanderhye P.C.
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