Background
Promptu Systems Corporation holds patents directed to systems that use remote speech recognition services in combination with cable television content delivery and control. The two asserted patents share a general subject matter — using voice recognition to interact with cable TV systems — but have materially different specifications. One patent covers using voice commands to deliver content (a content delivery patent), and the other covers using voice commands to control a user’s television (a control patent). Promptu sued Comcast Corporation, one of the nation’s largest cable providers, alleging infringement of both patents.
The district court construed several key claim terms — including “back channel,” “multiplicity of received identified speech channels,” “speech recognition system coupled to a wireline node,” and “centralized processing station” — and then granted judgment in favor of Comcast based on those constructions. Promptu appealed the claim constructions, arguing the district court had read limitations from specific embodiments in the specifications into the claims, thereby improperly narrowing their scope.
The Court’s Holding
The Federal Circuit reversed the district court’s constructions of multiple terms and vacated the judgment. The court reiterated the foundational claim construction principle that claim terms are generally given their plain and ordinary meaning as understood by a person of ordinary skill in the art at the time of the invention. Limitations from preferred embodiments described in the specification should not be read into claims unless the specification or prosecution history contains a clear, unambiguous disclaimer or express definition restricting the claim to those embodiments.
For each disputed term, the court found that the district court had improperly narrowed the claims to match specific features described in the specification. For example, the district court had interpreted “back channel” in a way that limited it to a particular communication pathway described in one embodiment, when the term’s plain meaning encompassed any return channel in a cable or communications system. Similarly, “centralized processing station” was interpreted too narrowly based on the specification’s preferred embodiment rather than the term’s ordinary technical meaning. The court vacated the judgment and remanded for new infringement proceedings applying the corrected constructions.
Key Takeaways
- Claim terms are presumed to carry their plain and ordinary meaning — courts may not restrict a claim term to a preferred embodiment described in the specification unless the specification expressly disclaims broader coverage or explicitly defines the term narrowly.
- The presence of a specific implementation in the specification does not mean the claim is limited to that implementation; claim scope and specification embodiments serve different functions.
- District courts that construe claims too narrowly by importing specification limitations create reversible error — the Federal Circuit will vacate infringement judgments that rest on overly narrow constructions.
- In disputes involving communication network patents (cable, wireless, wireline), technical terms like “back channel” and “processing station” will generally be construed according to their recognized meanings in the relevant technical field, not according to a single embodiment.
Why It Matters
Promptu v. Comcast is a reminder of one of the most common errors in patent claim construction: reading specific features of preferred embodiments into the claims. This error can dramatically narrow a patent’s scope and result in a finding of noninfringement on products that a skilled artisan would recognize as falling within the claim’s ordinary meaning. The Federal Circuit reversal and remand — which ultimately led to a $240 million jury verdict for Promptu in 2026 — illustrates how high the stakes are in getting claim construction right.
For patent holders asserting claims against technology companies, the decision reinforces the importance of appealing claim construction rulings that inappropriately narrow claim scope. For accused infringers, it illustrates that specification-based narrowing arguments — while sometimes effective — are only available when the specification contains an unambiguous disclaimer or definition, not merely a preferred embodiment.