Before Rader, Circuit Judge, Friedman and Archer, Senior Circuit Judges.
The opinion of the court was delivered by: Per Curiam.
Theis Research, Inc. (TRI) appeals the September 30, 1998 judgment *fn1 of the district court finding claims 1 and 14-19 of United States Patent No. 4,559,416 (`416 patent) invalid as anticipated. We affirm.
The `416 patent discloses a telephone line activity monitor that is used to monitor and record information indicative of the usage of one or more telephone lines. The `416 patent is owned by Peter Theis and licensed to TRI. TRI has an exclusive license with the right to sublicense and enforce the patent. TRI claims that the SL-1 PBX ACD-MAX option system sold by Northern Telecom, Inc. (NTI) infringes the `416 patent. The SL-1 OBX ACD-MAX option system enables the PBX switch to generate and record certain call processing information for each call (time of call and duration). It also permits an operator at a station to enter a variety of "activity codes" which identify the caller's account, the department to which the call is directed, or the product or service which is the subject of the call.
The `416 patent is one of six patents originally asserted by TRI in this action. The other five patents were addressed by the prior appeal, Octel Communications Corp. v. Theis Research, Inc., 132 F.3d 51 (Fed. Cir. 1997) (table) (Octel I). The `416 patent, which was only asserted against NTI, was severed from the trial on the other patents. Prior to the severance, however, NTI moved for summary judgment of invalidity of claims 1 and 14-19 of the `416 patent as being anticipated by NTI's SL-1 Multiport Call Detail Recording (CDR) system, which provided many of the call data generation and recording functions of the accused SL-1 PBX ACD-MAX option.
The district court granted NTI's motion with respect to claims 1 and 19, but found that an issue of fact existed with respect to the construction of claims 14-18, and denied summary judgment as to those claims. See Octel II, slip op. at 19. All proceedings as to the `416 patent were then stayed pending resolution of the issues surrounding the remaining five patents. Following this court's decision in Octel I, NTI sought reconsideration of the district court's denial of summary judgment as to the invalidity of claims 14-18, and TRI requested reconsideration of the district court's summary judgment of invalidity as to claims 1 and 19.
On reconsideration, the district court granted NTI's motion for reconsideration and found claims 14-18 were invalid as anticipated, and denied TRI's motion as to the invalidity of claims 1 and 19. See Octel III, slip op. at 19. This appeal followed.
This court reviews a district court's grant of summary judgment by reapplying the standard applicable at the district court. See Conroy v. Reebok Int'l, Ltd., 14 F.3d 1570, 1575, 29 USPQ2d 1373, 1377 (Fed. Cir. 1994). Summary judgment is appropriate only when "there is no genuine issue as to any material fact and . . . the moving party is entitled to judgment as a matter of law." Fed. R. Civ. P. 56(c). In its review, this court draws all reasonable inferences in favor of the non-movant. See Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 255 (1986).
TRI argues that the district court improperly construed "line activity monitor" in claims 1 and 19 because it misunderstood dependent claims 2, 5, 7, 20 and 21. Claim construction is a question of law which we review de novo. See Cybor Corp. v. FAS Techs., Inc., 138 F.3d 1448, 1456, 46 USPQ2d 1169, 1174 (Fed. Cir. 1998) (en banc).
In Octel III, the district court construed the limitation "a line activity monitor coupled to the telephone line to record information indicative of usage of the ...