KVM switch including a terminal emulator

• US 20070013656A1
• Filed: 09/19/2006
• Published: 01/18/2007
• Est. Priority Date: 08/25/1999
• Status: Active Grant

• Current Assignee: Vertiv IT Systems, Inc. (Vertiv Holdings Co.)
• Original Assignee: Avocent Redmond Corporation (Emerson Electric Company)
• Inventors: Shirley, Timothy
• Granted Patent: US 7,321,943 B2
• Time in Patent Office: Days
• US Class Current: 345/156
• CPC Class Codes: G06F 13/107 Terminal emulation
• CPC Class Codes: G06F 2203/0384 Wireless input, i.e. hardware and software details of wireless interface arrangements for pointing devices
• CPC Class Codes: G06F 3/023 Arrangements for converting discrete items of information into a coded form, e.g. arrangements for interpreting keyboard generated codes as alphanumeric codes, operand codes or instruction codes
• CPC Class Codes: G06F 3/038 Control and interface arrangements therefor, e.g. drivers or device-embedded control circuitry
• CPC Class Codes: G06F 3/14 Digital output to display device ; Cooperation and interconnection of the display device with other functional units
• CPC Class Codes: G09G 2370/24 Keyboard-Video-Mouse [KVM] switch
• CPC Class Codes: G09G 5/006 Details of the interface to the display terminal specific for a display terminal using a CRT G09G1/167; using a flat panel G09G3/2096; circuits for interfacing with colour displays G09G5/04

Abstract

A method and system for converting the output of a communications port (e.g., a serial port or a USB port) into video signals representing the output of a terminal using a KVM switch. Upon receiving characters from the communications port, the system interprets the characters as terminal emulation commands and internally generates a representation of what a resulting terminal screen would look like. From that internal (digital) representation, the system produces analog outputS representing the terminal screen. The analog outputs are output on the monitor attached to the KVM switch.

Claims

1. A KVM switch for connection to a monitor comprising:

a communications port configured to receive terminal commands;

a digital memory;

an analyzer configured to analyze the terminal commands and update a digital representation of a virtual terminal stored in the digital memory, based on the terminal commands;

a circuit configured to scan the digital memory and generate analog RGB signals and synchronization signals; and

analog drivers for driving the analog RGB signals out to the monitor.

2. The KVM switch as claimed in claim 1, wherein the circuit comprises plural bitmaps representing line-by-line representations of characters stored in the digital memory.

3. The KVM switch as claimed in claim 1, wherein the analyzer and the circuit are implemented in a field-programmable gate array.

4. The KVM switch as claimed in claim 3, further comprising a configuration memory, wherein the field-programmable gate array is dynamically loaded with a configuration, from the configuration memory, corresponding to a type of terminal to be emulated.

5. The KVM switch as claimed in claim 1, wherein the terminal commands are commands for a text-based terminal.

6. The KVM switch as claimed in claim 1, wherein the terminal commands are commands for a graphics-based terminal.

7. The KVM switch as claimed in claim 1, wherein the communications port comprises a wired communications port.

8. The KVM switch as claimed in claim 1, wherein the communications port comprises an Ethernet port

9. The KVM switch as claimed in claim 1, wherein the communications port comprises an RS-232 port.

10. The KVM switch as claimed in claim 1, wherein the communications port comprises a serial port.

11. The KVM switch as claimed in claim 1, wherein the communications port comprises a USB port.

12. The KVM switch as claimed in claim 1, wherein the communications port comprises a Token ring port.

13. The KVM switch as claimed in claim 1, wherein the communications port comprises an ATM port.

14. The KVM switch as claimed in claim 1, wherein the communications port comprises a wireless communications port.

15. The KVM switch as claimed in claim 1, wherein the communications port comprises an RF communications port.

16. The KVM switch as claimed in claim 1, wherein the communications port comprises an IR communications port.

17. The KVM switch as claimed in claim 1, wherein the communications port comprises a packet-based communications port.