US 6409602

US Patent 6,409,602: Slim Terminal Gaming System

Title: Slim terminal gaming system

Assignee: New Millenium Gaming LLC

Inventors: Michael S. Wiltshire, James J. Lisenbee, Jayant S. Karmarkar, Timothy A. Wiltshire

Filing Date: November 24, 1998

Issue Date: June 25, 2002

Abstract: The patent describes a computer gaming system and method designed to significantly reduce the cost of individual gaming stations while enabling concurrent access to multiple game programs from a single station. This is achieved by executing gaming and related management programs entirely on a central server/host computer. Remote client/terminal computers, connected via communication pathways, run a slim client/terminal program that separates and redirects the input and output streams of the server-executed gaming programs. Since the client/terminal computers only handle wagering input and display output, their hardware and software costs are substantially reduced. The system also allows for transparent modifications and upgrades to gaming programs and associated pay tables, and facilitates non-intrusive status monitoring for maintenance and regulatory purposes. An embodiment also describes a mobile gaming environment using a stereo head-mounted display, joystick, and wireless communication.

Plain-Language Overview of Independent Claims:

• Claim 1: Computer Gaming System (System Claim)
  This claim defines a gaming system composed of one or more central server computers and multiple simplified player terminals connected over a network. The key is that the actual game software runs entirely on the central server, not on the individual player terminals. A special "server/host interface program" on the server and a "client/terminal program" on each player terminal work together. Their function is to take the player's actions (input) and the game's visuals (output) from the main game running on the server, separate them, and send them back and forth across the network to the appropriate player terminal. This design allows the player terminals to be much less complex and expensive.

• Claim 15: Method of Operating a Computer Gaming System (Method Claim)
  This claim describes the process or steps involved in operating the gaming system outlined in Claim 1. It details how the gaming programs are executed on the central server, along with the server's interface program. Simultaneously, a client program runs on each player terminal. The core of the method involves taking the input and output generated by the game on the server, splitting these streams apart, and sending them to the remote player terminals using the server and client interface programs.

• Claim 28: Computer Gaming System with Multiple Gaming Threads (System Claim)
  This claim focuses on a server-based gaming system that supports multiple concurrent game experiences. It includes a central server computer running an operating system, at least two display devices, and at least two input devices (each linked to a display) connected to the server. The crucial aspect is that the server executes multiple "gaming threads" (essentially, multiple instances or concurrent processes) of one or more game programs. Each of these individual game threads is then specifically linked to and controls its own separate display and input device, allowing multiple players to interact with different game sessions from a single powerful server.

Litigation Status:

As of July 14, 2026, US Patent 6,409,602 itself is noted as "Expired - Lifetime" on Google Patents, indicating it is no longer in force. While there is no indication of active litigation directly involving US Patent 6,409,602 in the CAFC 2026 dockets, it was cited as a primary prior art reference in a recent CAFC case, Intellectual Pixels Limited v. Sony Interactive Entertainment LLC, decided on July 10, 2026. In that case, Sony Interactive Entertainment LLC successfully relied on US Patent 6,409,602 to argue that claims 1 through 12 of U.S. Patent No. 10,681,109 were unpatentable as obvious, a decision that the Federal Circuit affirmed. This demonstrates the relevance of US Patent 6,409,602 as prior art, even after its expiration.

Based on the available information and search results as of April 26, 2026, there is no known active or concluded litigation directly involving US Patent 6,409,602 as an asserted patent for infringement or a patent whose validity is being challenged in a standalone case.

The patent, US Patent 6,409,602, is noted as "Expired - Lifetime" on Google Patents, which means it is no longer in force and cannot be asserted for infringement.

However, US Patent 6,409,602 has been prominently cited as a prior art reference in other patent litigation. Notably, in Intellectual Pixels Limited v. Sony Interactive Entertainment LLC, the U.S. Court of Appeals for the Federal Circuit (CAFC) affirmed a Patent Trial and Appeal Board (PTAB) decision that held claims 1 through 12 of U.S. Patent No. 10,681,109 unpatentable as obvious, with Sony's petition relying primarily on US Patent 6,409,602. This decision was issued on July 10, 2026. While this demonstrates its relevance in prior art challenges, it is not a case where US Patent 6,409,602 itself was the subject of an infringement suit or a validity challenge.

Proceedings overview

There are no AIA trial proceedings (Inter Partes Review, Post-Grant Review, or Covered Business Method review) on file for US Patent 6,409,602. This status suggests that the patent has not been subjected to challenges at the Patent Trial and Appeal Board (PTAB) under the America Invents Act. For a defendant facing potential assertion related to this patent, this means all claims remain legally intact as granted, and there is no PTAB decision to leverage for invalidity arguments or to assess the "hardened" status of the patent's claims.

Strategic summary

As of July 14, 2026, no claims of US Patent 6,409,602 have been challenged or invalidated through AIA trial proceedings at the PTAB. All 29 claims of the patent, therefore, remain untested by this specific avenue of post-grant review.

The absence of PTAB proceedings means there is no estoppel landscape to consider under 35 U.S.C. § 315(e)(2) for any potential petitioner or their privies. All prior art grounds remain available for a defendant to assert in district court litigation or to use in a newly filed AIA trial, should that be deemed strategically viable (though the patent's "Expired - Lifetime" status on Google Patents, indicating expiration on 2018-11-06, would preclude new AIA trials).

There is no discernible pattern of PTAB activity, as no proceedings have been filed. The patent has not been actively defended or challenged at the PTAB by any patent owner or petitioner.

Recommended next steps

Given that US Patent 6,409,602 is listed as "Expired - Lifetime" with an anticipated expiration date of 2018-11-06, and there are no PTAB proceedings on file:

• No PTAB activity to leverage: A defendant currently facing assertion of this patent cannot rely on any prior PTAB invalidation of claims. All claims are presumed valid as issued.
• No new PTAB challenges possible: Due to the patent's expiration in 2018, it is no longer possible to initiate new AIA trial proceedings (IPR, PGR, or CBM) against US Patent 6,409,602. These proceedings can only be filed against unexpired patents.
• Defensive posture: Any defensive strategy would need to focus on other avenues, such as prior art searches for invalidity arguments in district court (if litigation were to arise concerning past infringement during the patent's lifetime), non-infringement arguments, or licensing negotiations. The mention of US6409602 being successfully used as prior art in Intellectual Pixels Limited v. Sony Interactive Entertainment LLC highlights its foundational nature but does not impact the validity of its own claims.
• Source Confirmation: The "USPTO ODP API returns no AIA trial proceedings for this patent as of the most recent ingest" is confirmed by web searches for "US patent 6409602 PTAB," "US6409602 IPR," "US6409602 PGR," and "US6409602 CBM," which yield no records of such proceedings.

Inventors

• Michael S. Wiltshire: Employer at time of filing was implicitly New Millenium Gaming LLC, the original assignee.
• James J. Lisenbee: Employer at time of filing was implicitly New Millenium Gaming LLC.
• Jayant S. Karmarkar: Employer at time of filing was implicitly New Millenium Gaming LLC.
• Timothy A. Wiltshire: Employer at time of filing was implicitly New Millenium Gaming LLC.

There are no immediately determinable unusual patterns, such as inventors departing the original assignee shortly after filing, based on the information available in the patent document.

Original assignee

The entity named on the issued patent US6409602 is New Millenium Gaming LLC. Their primary line of business, as described by the patent, was the development of a "Slim terminal gaming system" (US6409602, Title). The patent's abstract and description detail a client-server architecture for computer-implemented gaming systems aimed at reducing costs and increasing tamper resistance for individual gaming stations.

As of July 14, 2026, the current operational status of New Millenium Gaming LLC (as a product-shipping entity) is unclear from readily available public records. The patent itself expired in November 2018, meaning its legal enforceability ceased.

Assignment timeline

According to a search of the USPTO Patent Assignment Search database (https://assignmentcenter.uspto.gov/) for patent number US6409602, there are no recorded assignments for this patent. The Google Patents record indicates an initial assignment on the filing date from the inventors to "NEW MILLENIUM GAMING LIMITED" (possibly a variant or predecessor of "New Millenium Gaming LLC"), but this is an initial transfer upon application filing and not a subsequent recorded assignment in the USPTO database.

Timeline diagram

timeline
    title Ownership of US 6409602
    1998 : Filed by New Millenium Gaming LLC
    2002 : Issued to New Millenium Gaming LLC
    2018 : Patent expired

NPE / troll-pattern signals

1. Shell-entity transfer — not present. No assignment records found on USPTO.
2. Known asserter in the chain — not present. No assignment records found on USPTO.
3. Repeat correspondent across the chain — not present. No assignment records found on USPTO.
4. Cascading transfers — not present. No assignment records found on USPTO.
5. Pre-litigation transfer — not present. No assignment records found on USPTO.
6. Bankruptcy fire-sale — not present. No assignment records found on USPTO to indicate a sale, and no readily available public records indicate a bankruptcy filing for New Millenium Gaming LLC.
7. Privateering — not present. No assignment records found on USPTO.
8. Defensive aggregator (anti-NPE) — not present. No assignment records found on USPTO.

Verdict

Insufficient data.

There are no recorded assignments for US Patent 6409602 in the USPTO Patent Assignment Search database (https://assignmentcenter.uspto.gov/), beyond the initial implicit assignment from inventors to the original assignee at filing. Without any subsequent transfer records, it is impossible to determine if the patent was ever transferred to an NPE or an operating company post-issuance. The patent expired in 2018, further limiting the relevance of its current ownership.

The search results confirm the details of US Patent 4,448,419 (Telnaes).

Here's the analysis for the identified prior art:

Most Relevant Prior Art for US Patent 6,409,602

Based on the provided full patent text for US6409602B1, the most explicitly cited prior art patent within the detailed description of the invention is U.S. Pat. No. 4,448,419.

Prior Art Reference 1:

• Full Citation: U.S. Pat. No. 4,448,419 to Telnaes, entitled “Electronic Gaming Device Utilizing a Random Number Generator for Selecting the Reel Stop Positions.”

• Publication/Filing Date:

  • Filing Date: February 24, 1982
  • Issue/Publication Date: May 15, 1984

• Brief Description: This patent describes a gaming apparatus, specifically a slot machine, that uses rotating reels with indicia on their periphery. The key innovation is the use of a random number generator (RNG) to select the reel stopping positions, rather than relying solely on the physical stops of the mechanical reels. This allows for controlling payout odds independently of the physical characteristics of the machine, by assigning numbers to reel stopping positions and entering them into the RNG with varying frequencies. The physical reels essentially act as a display for the RNG's result.

• Potential Anticipation under 35 U.S.C. § 102:
  U.S. Pat. No. 4,448,419 primarily anticipates aspects related to electronic gaming devices and the use of digital means (RNGs) to determine game outcomes for a display, particularly mechanical reels.

  • General Concept of Electronic Gaming: It anticipates the fundamental idea of an electronic gaming device that presents a game of chance to a user.
  • Gaming Device with Display and Input (Implicit): While not explicitly describing a "client/terminal computer" in the sense of US6409602B1, it describes a "gaming apparatus" or "slot machine" which inherently includes a display (the reels) and an input mechanism (e.g., a lever to set reels in motion). This could broadly anticipate elements like a "display device" and "wager-acceptor device" as mentioned in claims 4 and 5 of US6409602B1.
  • Mechanical Reel Display: The patent directly teaches the use of mechanical reels to display game results, including "virtual reel" technology. US6409602B1 mentions that "display devices 140 may also include a mechanical reel system, in lieu of or in combination with a monitor, to display game results using “virtual reel” technology as described, for example, in U.S. Pat. No. 4,448,419". This indicates that the display technology itself, including virtual reels, is not novel to US6409602B1.
  • Limited Anticipation of Core Claims: However, U.S. Pat. No. 4,448,419 does not anticipate the core innovative aspects of US6409602B1, which revolve around a client-server architecture where game programs are executed exclusively on a server/host computer and input/output streams are redirected to "slim" client/terminal computers. The Telnaes patent describes a self-contained "electronic gaming device" where the random number generation and reel stopping logic are local to the machine itself. Therefore, it would not anticipate elements of claims 1, 15, and 28 that define the distributed processing model (e.g., "one or more computer gaming programs executed on at least one server/host computer but not on any of the client/terminal computers", "separating input and output streams at an application layer of a protocol stack, and redirects the input and output streams over the communication pathways to the client/terminal computers").

  More specifically:

  • It does not anticipate Claim 1 and Claim 15 regarding the server/host computer executing game programs not on client/terminal computers, and the separation/redirection of I/O streams over communication pathways.
  • It does not anticipate Claim 28's emphasis on multiple gaming threads on a server controlling separate display/input devices, as it describes a single, self-contained gaming machine.
  • It could potentially serve as a basis for obviousness arguments (35 U.S.C. § 103) in combination with other prior art teaching networking and thin clients, when considering the broad aspects of "a gaming system" or "a gaming program." However, as a direct anticipation under § 102 for the fundamental client-server architecture of US6409602B1, its scope is limited to the local electronic gaming device with a virtual reel display.Based on the provided full patent text for US Patent 6,409,602, the most explicitly cited prior art patent within the detailed description of the invention is U.S. Pat. No. 4,448,419.

Most Relevant Prior Art for US Patent 6,409,602

Prior Art Reference 1:

• Full Citation: U.S. Pat. No. 4,448,419 to Telnaes, entitled “Electronic Gaming Device Utilizing a Random Number Generator for Selecting the Reel Stop Positions.”

• Publication/Filing Date:

  • Filing Date: February 24, 1982
  • Issue/Publication Date: May 15, 1984

• Brief Description: This patent details a gaming apparatus, specifically a slot machine, that employs rotating reels with symbols on their periphery. Its core innovation lies in using a random number generator (RNG) to determine the reel stopping positions, thereby decoupling the game's payout odds from the physical configuration of the mechanical reels. This allows for dynamic control over payout probabilities by adjusting the frequency with which numbers corresponding to specific reel positions are assigned within the RNG. The physical reels function primarily as a visual display of the game outcome determined by the RNG.

• Potential Anticipation under 35 U.S.C. § 102:
  U.S. Pat. No. 4,448,419 potentially anticipates certain broad aspects of electronic gaming devices, but not the specific client-server architecture central to US6409602B1.

  • General Electronic Gaming Device: It anticipates the foundational concept of an electronic gaming device that offers a game of chance to a user.
  • Gaming Device with Display and Input: While not describing a "client/terminal computer" in the context of US6409602B1's networked system, it defines a "gaming apparatus" or "slot machine" which inherently includes a display (the reels) and an input mechanism (e.g., a lever). This could broadly be seen as anticipating components such as a "display device" and a "wager-acceptor device" as outlined in claims 4 and 5 of US6409602B1.
  • Mechanical Reel Display: The patent directly teaches the use of mechanical reels as a display for game results, specifically mentioning "virtual reel" technology. The description of US6409602B1 explicitly references U.S. Pat. No. 4,448,419 when discussing that "display devices 140 may also include a mechanical reel system... to display game results using “virtual reel” technology". This confirms that the concept of virtual reel display technology itself was prior art to US6409602B1.

  However, U.S. Pat. No. 4,448,419 does not anticipate the core inventive elements of US6409602B1. The Telnaes patent describes a self-contained gaming machine where the game logic (RNG and reel control) is executed locally. It does not disclose a system where:

  • Game programs are executed exclusively on a server/host computer and not on any client/terminal computers.
  • Input and output streams are separated at the application layer of a protocol stack and redirected over communication pathways between a server and client terminals.
  • A server/host computer handles multiple gaming threads for multiple remote display and input devices.

  Therefore, U.S. Pat. No. 4,448,419 would generally not anticipate the system claims (Claim 1 and Claim 28) or the method claim (Claim 15) of US6409602B1 concerning its innovative client-server architecture and distributed processing model. Its relevance under § 102 is primarily limited to the characteristics of the gaming device's display and internal game mechanics, particularly regarding virtual reels, rather than the networked system architecture.

Obviousness Analysis of US Patent 6,409,602 under 35 U.S.C. § 103

This analysis evaluates whether the independent claims of US Patent 6,409,602 would have been obvious to a person having ordinary skill in the art (POSITA) as of its November 6, 1998 priority date, based on the prior art described within the patent itself and general knowledge at that time.

The patent identifies several issues with existing computer gaming systems in its "BACKGROUND OF THE INVENTION" section:

• High manufacturing cost of individual gaming stations, often due to dedicated hardware and on-board game program execution.
• Difficulty and downtime associated with modifying and upgrading game programs, as it typically required physical access and hardware changes to individual stations.
• Lack of concurrent access to multiple games from a single station.
• Limitations of existing "clustered gaming stations" where game programs, even if downloaded from a central computer, were still executed "in whole or in part on the individual gaming station".
• Casino gaming websites existed where applets (e.g., JAVA™ bytecodes) were downloaded and executed on the user's computer (client-side execution of game logic).

The core innovation claimed by US Patent 6,409,602 is the execution of gaming programs "exclusively on a server/host computer," with client/terminal computers performing "only input wagering and output screen display related operations". This design drastically reduces client cost, increases tamper resistance, allows transparent upgrades, and enables concurrent access to multiple games from one terminal.

A POSITA in the field of computer gaming systems in 1998 would have possessed knowledge of existing gaming systems and commonly available general-purpose computing technologies.

Combination of Prior Art for Obviousness

The independent claims (Claims 1, 15, and 28) would likely have been obvious as a combination of:

1. Prior Art Computer Gaming Systems: As described in the patent's "BACKGROUND OF THE INVENTION" (Column 1, lines 16-34), these systems comprised individual gaming stations with display devices, wager-acceptors, and controls. Some systems included a "central computer" that could "download" game programs to "a cluster of gaming stations" and allow players to compete against each other. This prior art establishes the basic components and operational context of gaming machines and networked gaming.

2. General-Purpose Remote Display/Application Sharing Technologies: The patent's "DETAILED DESCRIPTION OF THE EMBODIMENTS" explicitly identifies and lists several commercially available products as examples of the server/host interface program 114 and client/terminal program 122. These include:

   • Citrix WinFrame® or MetaFrame™
   • Microsoft Windows NT Server 4.0 Terminal Server Edition™
   • Tarantella™ from The Santa Cruz Operation, Inc.
   • Go-Global™ from Graphon Corp.
   • Liftoff® server from New Moon Software, Inc.
   • Applica U2 or Applica Workgroup from Concurrent Controls, Inc.
   • Netwinder WS from Corel Computer Corp.

   These technologies, well-known before the 1998 priority date, enabled applications to execute entirely on a central server, with client machines (often "thin clients" or "dumb terminals") merely receiving screen updates (output streams) and transmitting user interactions (input streams) back to the server. They inherently provided the functionality of "separat[ing] input and output streams at an application layer of a protocol stack, and redirect[ing] the input and output streams over the communication pathways to the client/terminal computers".

3. General Knowledge of Multi-threading Operating Systems: The patent describes the use of an "operating system 116" on the server that "allows multiple gaming threads of game program 112 to be executed at one time," facilitating "preemptive multitasking" (Column 5, lines 51-66). Operating systems with multi-threading and multitasking capabilities, such as Windows NT (mentioned as a possible server/host operating system 116 in Column 6, lines 40-41), were standard and widely understood by 1998.

Motivation to Combine

A POSITA would have been highly motivated to combine these known elements to address the well-understood problems in the gaming industry:

• Cost Reduction: The primary motivation would be to "drastically reduce[] the cost" of gaming stations. Traditional gaming machines with on-board processing were expensive. By adopting the thin-client architecture enabled by technologies like Citrix or Windows NT Terminal Server, the expensive processing hardware could be centralized on a powerful server, allowing for much cheaper, simpler client terminals that only needed to handle I/O. This directly addresses the problem of manufacturing cost (Column 2, lines 4-6).
• Centralized Management and Easier Upgrades: Managing and updating software on numerous individual gaming machines was cumbersome and caused downtime (Column 2, lines 7-9). Remote display/application sharing technologies offered inherent centralized application management, meaning game modifications and upgrades could be performed once on the server, transparently and with minimal disruption to the gaming stations. This directly solves the identified problem and provides "transparent modifications and upgrades to the computer gaming programs".
• Increased Tamper Resistance: With the core game logic (including random number generation, as taught by Telnaes U.S. Pat. No. 4,448,419) residing entirely on a secure central server, the less complex and more physically exposed client terminals would be less susceptible to tampering. This fulfills the patent's goal of "substantially increas[ing] the tamper resistance of individual gaming stations".
• Concurrent Access to Multiple Games: Dedicated gaming machines were limited to one game (Column 1, lines 20-22). By running multiple game programs or multiple threads of a single game program on a server, and redirecting I/O to a thin client, a single client terminal could easily switch between different games, providing "concurrent access to multiple computer gaming programs from individual gaming stations" without hardware changes.
• Regulatory Monitoring and Maintenance: Centralized game execution also facilitated easier "fairness or regulatory compliance" monitoring and "periodic maintenance" by authorized regulators and maintenance staff (Column 2, lines 35-39).

The application of a well-known client-server architecture, specifically remote display technology, to the established field of computer gaming to achieve these predictable and desirable advantages would have been an obvious design choice for a POSITA in 1998. The commercial availability and widespread understanding of technologies like Citrix WinFrame/MetaFrame demonstrated the feasibility and benefits of such a server-centric, thin-client approach for various applications, making its extension to gaming systems a matter of routine implementation rather than inventive ingenuity.