US 6,611,537 · Granted 2003-08-26

The Patent That Turned Phone Lines Into a Digital Media Superhighway

Imagine converting your boring old telephone wiring into a high-speed network that sends music, video, and commands around your house in perfect sync. This patent describes a clever adapter that creates a logical ring network on existing phone lines, with all devices locked to the same clock so data always arrives on time.

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The plain-English version

What it protects

The claim covers a network adapter that takes existing twisted-pair telephone cabling and creates a synchronized logical ring topology on top of it. What's protected here is the specific method of having all network devices operate in full-duplex mode (transmitting and receiving simultaneously on every clock cycle), elect a single reference clock device, and divide information into fixed-length frames split between a real-time digital media stream and a system command stream. The key protection is the combination of synchronous operation, fixed frame timing, and dual-stream architecture running over standard phone line infrastructure.

Why it matters

In the late 1990s and early 2000s, home networking was fragmented and messy. This patent protected an elegant approach: reuse the phone wiring already running through walls and ceilings to create a synchronized digital network. By guaranteeing consistent timing for real-time media (like audio and video) while also handling control commands, this architecture solved a real problem for consumer electronics makers trying to distribute entertainment throughout homes without ripping out walls. The synchronous approach meant multimedia would never arrive choppy or out of sync.

Real-world use

When a home entertainment system needs to send audio to multiple speakers and video to multiple displays simultaneously without lag, technologies based on this synchronization method ensure every device receives its data in lockstep.

Original USPTO abstract

A network adapter for a synchronous logical ring network operates on existing physical twisted-pair telephone topologies. Information propagates around the logical ring, reaching every device on each revolution around the network. Network devices are full-duplex, transmitting and receiving information on every clock cycle. Network devices arbitrate to be elected the network clock device. By synchronizing all network devices to a single reference clock, and providing fixed frames of information propagating around the network at consistent time intervals, the logical ring network ensures that information propagates from one device to another at consistent time intervals. The fixed-length frames are divided into two independent streams: a data stream for the distribution of real-time continuous digital media streams; and a system command stream for the distribution of system commands.

Patent details

Publication number: US 6,611,537
Filing date: 1998-05-15
Grant date: 2003-08-26
Assignee: Centillium Communications, Inc.
Inventor(s): EDENS GLENN T., HOOVER DONALD ROBERT, MEIKE ROGER CHARLES, RYAN TIMOTHY ANDREW
CPC class: H04L12/2832

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