United States Court of Appeals 

for the Federal Circuit ______________________ 

FENNER INVESTMENTS, LTD.,

Plaintiff-Appellant

v.

CELLCO PARTNERSHIP 

(doing business as Verizon Wireless),

Defendant-Appellee

______________________ 

2013-1640

______________________ 

Appeal from the United States District Court for the 

Eastern District of Texas in No. 11-CV-0348, Judge 

Leonard Davis.

______________________ 

Decided: February 12, 2015

______________________ 

JONATHAN S. FRANKLIN, Norton Rose Fulbright US 

LLP, Washington, DC, argued for plaintiff-appellant. 

Also represented by MARK EMERY. 

GEOFFREY P. EATON, Winston & Strawn LLP, Washington, DC, argued for defendant-appellee. Also represented by KEVIN PAUL ANDERSON, KARIN A. HESSLER,

Wiley Rein, LLP, Washington, DC; CAREN KHOO, Verizon 

Corporate Services Group, Basking Ridge, NJ.

______________________ 
2 FENNER INVESTMENTS, LTD. v. CELLCO PARTNERSHIP

Before NEWMAN, SCHALL, and HUGHES, Circuit Judges.

NEWMAN, Circuit Judge.

Fenner Investments, Ltd. appeals from the district 

court’s grant of summary judgment that Cellco Partnership, doing business as Verizon Wireless, does not infringe claim 1 of United States Patent No. 5,561,706 (the 

’706 patent). We affirm the judgment. 

BACKGROUND

The ’706 patent is directed to personal communication 

services (PCS) systems, whereby users are provided with 

the ability to access a communications network from 

diverse locations. Before the development of PCS systems, call servicing and billing were specific to a particular communications device at a fixed location. In PCS 

systems, telephone service can be identified independent 

of a telephone unit, and each user of a particular device 

has a personal identification number by which call servicing and billing are identified with the user, and not with a 

particular telephone unit. ’706 Patent col. 1 ll. 15-45.

The ’706 patent states that “a need has arisen for a 

system capable of locating and tracking personal identification numbers such that billing and connecting procedures may be accomplished” in order to realize the 

benefits of uncoupling devices and individual users operating in a PCS system. Col. 1 ll. 43-45. The ’706 patent 

states that existing PCS systems do not address this need 

because “present telephone communication numbering 

and addressing systems are geographically oriented since 

the source telephone and the destination telephone numbers are always in predictable and set locations.” Col. 1 ll. 

32-35. The ’706 invention seeks to address this problem

“by means of a mobile address management system” that 

“uses multiple location authorities to track the locations 
FENNER INVESTMENTS, LTD. v. CELLCO PARTNERSHIP 3

of personal identification numbers and multiple billing 

authorities to maintain the services and the billing costs 

associated with a personal identification number.” Col. 1 

ll. 49-54.

Claim 1, the only asserted claim of the ’706 patent, 

states the patented method: 

1. A method of providing access to a mobile user 

in a communications system having a plurality of 

interconnected radio frequency communication 

switches for selectively collecting calls to mobile 

users via radio frequency links, a plurality of billing authorities for maintaining service profiles of 

mobile users and a plurality of location authorities for maintaining current locations of mobile 

users within the interconnected communication 

switches, the method comprising:

receiving at a radio frequency communication 

switch a personal identification number from 

a mobile user;

receiving from the mobile user at the communication switch a billing code identifying one of the 

plurality of billing authorities maintaining a 

service profile for the mobile use[r], wherein 

different ones of the plurality of billing authorities may maintain the service profile or a 

second profile for the mobile user identified by 

the personal identification number;

requesting a service profile of the mobile user 

from the billing authority identified by the received billing code;

storing in memory the service profile received 

from the billing authority; and

providing the mobile user access to the switch.

After a claim construction hearing, the district court 

adopted Verizon’s proposed construction of the term 
4 FENNER INVESTMENTS, LTD. v. CELLCO PARTNERSHIP

“personal identification number,” construing it to mean “a 

number separate from a billing code (as construed herein), 

identifying an individual system user, which is associated 

with the individual and not the device.” The district court 

construed “billing code” to mean “a code separate from the 

personal identification number (as construed herein), 

identifying a particular billing authority (as construed 

herein).” Based on the court’s designated meaning of 

these terms, the parties stipulated to final judgment of 

noninfringement, subject to Fenner’s right to appeal. 

DISCUSSION

We review de novo the ultimate question of the proper 

construction of patent claims and the evidence intrinsic to 

the patent. Teva Pharm. USA, Inc. v. Sandoz, Inc., 135 S. 

Ct. 831, 841 (2015); id. (“[W]hen the district court reviews 

only evidence intrinsic to the patent (the patent claims 

and specifications, along with the patent’s prosecution 

history), the judge’s determination will amount solely to a 

determination of law, and the Court of Appeals will 

review that construction de novo.”). The district court’s 

determination of subsidiary facts based on extrinsic 

evidence is reviewed for clear error. Id. at 835, 841.

The district court’s definition of “personal identification number” is the issue on this appeal. Fenner argues 

that the district court erred by construing “personal 

identification number” as a number that is associated 

with the individual user and not with the device. Fenner

argues that the plain meaning of “personal identification 

number” does not contain or require this limited definition, and that the district court erroneously imported this

limitation from the specification and erroneously relied on 

the prosecution history to support this construction.

The terms used in patent claims are not construed in 

the abstract, but in the context in which the term was 

presented and used by the patentee, as it would have been 

understood by a person of ordinary skill in the field of the 
FENNER INVESTMENTS, LTD. v. CELLCO PARTNERSHIP 5

invention on reading the patent documents. See Biogen 

Idec, Inc. v. GlaxoSmithKline LLC, 713 F.3d 1090, 1095 

(Fed. Cir. 2013) (“[A] term’s ordinary meaning must be 

considered in the context of all the intrinsic evidence, 

including the claims, specification, and prosecution history.”). Thus, a claim receives the meaning it would have to 

persons in the field of the invention, when read and 

understood in light of the entire specification and prosecution history. Phillips v. AWH Corp., 415 F.3d 1303, 1312–

1317 (Fed. Cir. 2005) (en banc). Any explanation, elaboration, or qualification presented by the inventor during 

patent examination is relevant, for the role of claim 

construction is to “capture the scope of the actual invention” that is disclosed, described, and patented. Retractable Techs., Inc. v. Becton, Dickinson & Co., 653 F.3d 1296, 

1305 (Fed. Cir. 2011). 

Words are symbols, linguistic embodiments of information sought to be communicated, and, as such, can be 

imperfect at representing their subject. The Supreme 

Court recently observed this challenge to patent claim

interpretation, stating in Nautilus, Inc. v. Biosig Instruments, Inc., 134 S. Ct. 2120, 2128-29 (2014), that “the 

definiteness requirement must take into account the 

inherent limitations of language,” and that clarity is 

required although “recognizing that absolute precision is 

unattainable.” When the disputed words describe technology, the terse usage of patent claims often requires 

“construction” in order to define and establish the legal 

right. Judicial “construction” of patent claims aims to 

state the boundaries of the patented subject matter, not to 

change that which was invented.

A. The Written Description

The foundation of judicial claim construction is the 

“written description” in the specification. The patent 

statute requires that the claims “particularly point[] out 

and distinctly claim[] the subject matter” that the appli-
6 FENNER INVESTMENTS, LTD. v. CELLCO PARTNERSHIP

cant regards as the invention. 35 U.S.C. §112(b). The 

district court appropriately consulted the description in 

the ’706 specification “for the purpose of better understanding the meaning of the claim.” White v. Dunbar, 119 

U.S. 47, 51 (1886).

The ’706 specification includes block diagrams and 

flow charts, typified by Figure 1.

Such drawings are part of the “written description” of the 

invention. The text of the ’706 patent states: “Referring 

now to Fig. 1, wherein there is shown a block diagram of 

the present invention. . . . The personal identification 

numbers 2 are not associated with any particular communications unit or physical location but are associated 

with individual users.” ’706 Patent col. 2 ll. 30-36. Verizon argues that this description limits the available scope 

of claim 1. See, e.g., Verizon Servs. Corp. v. Vonage Holdings Corp., 503 F.3d 1295, 1308 (Fed. Cir. 2007) 

(“[D]escrib[ing] the features of the ‘present invention’ as a 

whole . . . limits the scope of the invention.”). 
FENNER INVESTMENTS, LTD. v. CELLCO PARTNERSHIP 7

The patent explains that this system is distinguished 

from non-PCS telephonic communications systems whose

“billing and system management procedures are associated with the telephones present in a household or business” and “billing charges are associated with the 

telephone and not with the individual making the call.” 

’706 Patent col. 1 ll. 16-22. Describing the PCS system as 

centered on the user instead of the device, the patent 

describes the “PCS concept envision[ing] each telephone 

user having a personal identification number” and 

“[b]illing and call servicing are identified with the individual personal identification numbers and not with a 

telephone unit.” Col. 1 ll. 24-30.

The patent points out that the “individualized nature 

of a PCS system raises several problems,” such as how to 

“locat[e] and track[] personal identification numbers such 

that calls can be set up with and billed to the proper 

user.” Col. 1 ll. 30-31, 37-40. The patent states that its

invention “overcomes” these problems and accomplishes 

the tracking of location and billing authority through a 

user-centered system in which users have personal identification numbers that are associated with the individual 

user, but not a particular communications unit or physical 

location. Col. 1 l. 49; col. 2 ll. 35-37. The district court 

construed claim 1 as subject to the limitation that the 

personal identification number identify and associate 

with the user and not the device, for claim 1 states that a 

“personal identification number” is received “from a 

mobile user” and the “plurality of billing authorities may 

maintain the service profile or a second profile for the

mobile user identified by the personal identification 

number.” Col. 6 ll. 3-11.

The patent also describes a “fraud protection means” 

that

uses a check out protocol to determine if a personal identification number 2 is active in only one lo-
8 FENNER INVESTMENTS, LTD. v. CELLCO PARTNERSHIP

cation. When a personal identification number is 

found to be active in two non-adjacent locations . . . the switch node attempting to check out 

the personal identification number is sent a fraud 

error message.

Col. 3 ll. 5-12. Verizon argues that this control further demonstrates that the ’706 patent is for a usercentered method in which the personal identification 

number is associated with a user, not a device-centered

method. 

B. The Prosecution History

The prosecution history bolsters the district court’s 

construction that the term “personal identification number” is a number associated with the user, not the device. 

See Phillips, 415 F.3d at 1317 (“[L]ike the specification, 

the prosecution history was created by the patentee in 

attempting to explain and obtain the patent.”). 

During prosecution, the patent examiner rejected 

Fenner’s claims for obviousness in view of U.S. Patent No. 

5,210,787 (“Hayes”). Hayes describes a system in which 

contact to a communications system is maintained 

through a process of “registration.” Hayes col. 1 l. 55 to 

col. 2 l. 5; col. 2 l. 65 to col. 3 l. 10. The Hayes registration 

process involves a mobile device periodically receiving a 

signal from a base station, which signal includes information identifying the base station system, referred to as 

a “system identification number”; the mobile device 

responds to the base station signal by sending a “mobile 

identification number” and its electronic serial number for 

registration. Id. col. 1 ll. 57-67.

Fenner overcame this rejection by stressing that 

Hayes is a device-centered communication system, in 

contrast to Fenner’s user-centered design. Fenner argued 

that the mobile identification number of Hayes “is equivalent to a typical wireline telephone number since it must 
FENNER INVESTMENTS, LTD. v. CELLCO PARTNERSHIP 9

be assigned to a particular mobile communication switch 

or home exchange, much like a wireline telephone is.” 

J.A. 2508. Distinguishing Hayes, Fenner stated that 

“[t]he present invention, on the other hand, is centered

around the mobile user, not the mobile telephone. The 

user is identified by a personal code. Furthermore, the 

mobile user need not be, unlike a mobile telephone, assigned to a particular home exchange.” J.A. 2509.

Fenner argues that these purportedly limiting statements he made during prosecution do not limit the claims, 

arguing that the statements and the limitations discussed 

were not the basis for grant of the patent. However, the 

interested public has the right to rely on the inventor’s 

statements made during prosecution, without attempting 

to decipher whether the examiner relied on them, or how 

much weight they were given. See Microsoft Corp. v. 

Multi-Tech Sys., Inc., 357 F.3d 1340, 1350 (Fed. Cir. 2004) 

(“[A] patentee’s statements during prosecution, whether 

relied on by the examiner or not, are relevant to claim 

interpretation.”); Laitram Corp. v. Morehouse Indus., Inc., 

143 F.3d 1456, 1462 (Fed. Cir. 1998) (“The fact that an 

examiner placed no reliance on an applicant’s statement 

distinguishing prior art does not mean that the statement 

is inconsequential for purposes of claim construction.”).

As the district court observed, the prosecution history 

does not show or suggest that Fenner contemplated any 

alternative to a personal identification number associated 

with the individual and not with the device.

C. Inoperability

Fenner argues that the district court’s claim construction of “personal identification number” to mean “associated with the individual and not the device” cannot be 

correct because it renders the patented invention inoperable. Fenner states that only a device (not a person) is

capable of transmitting the personal identification number to a radio-frequency communication switch, and that 
10 FENNER INVESTMENTS, LTD. v. CELLCO PARTNERSHIP

“a human being cannot communicate with such a switch 

except through a compatible radio-equipped cell phone or 

other wireless unit.” Appellant Br. 25. The ’706 patent, 

col. 6 ll. 3-4, refers to “receiving at a radio frequency 

communication switch a personal identification number 

from a mobile user,” an activity performed by a device, not 

by a person. 

Fenner argues that the district court’s claim construction means that “there can never be any association 

between the personal identification number and the 

device” and, thus, is incorrect. Appellant Br. 28. However, the district court’s construction requires only that a 

personal identification number is not permanently associated with a specific communications unit or location. This 

construction is not flawed.

D. Claim Differentiation

Fenner also argues that the doctrine of claim differentiation negates the district court’s construction, for claim 

19 would become redundant or superfluous if claim 18 is 

construed with the restriction imposed by the district 

court. Claim 18 reads:

In a communications network having a plurality 

of interconnected communication switches, and in 

which users are identified by a personal identification code wherever that user is located within 

the communications network, a method for completing a call from a source to a destination user 

comprising:

receiving from a source user logged onto a first 

communication switch a personal identification code of a destination user to whom a call 

is to be routed:

determining whether the destination user is currently logged onto the first communication 

switch; and
FENNER INVESTMENTS, LTD. v. CELLCO PARTNERSHIP 11

if the destination user is not logged onto the first 

communication switch,

identifying a location tracking authority assigned to the personal identification code 

of the destination user,

requesting from the location tracking authority an identity for a destination communication switch on which the destination 

user is currently logged onto,

receiving the identity of the destination communication switch at the first communication switch, and

routing the call to the destination switch.

’706 Patent col. 8 ll. 33-55. Claim 19 states: “The 

method of claim 18 wherein the personal identification 

number of the source and the destination user are independent of a particular physical communications unit.” 

Id. col. 8 ll. 56-58. 

Fenner argues that since claim 19 is specific to the

method where the personal identification number is 

independent of the device, the doctrine of claim differentiation requires that the foundation claims such as claims 1 

and 18 are not so limited. Fenner argues that “if the term 

personal identification number always means that the 

number is never associated with any device . . . the limitation in Claim 19 would have been unnecessary.” Appellant Br. 29.

Although claim differentiation is a useful analytic 

tool, it cannot enlarge the meaning of a claim beyond that 

which is supported by the patent documents, or relieve 

any claim of limitations imposed by the prosecution 

history. See, e.g., Retractable Techs., 653 F.3d at 1305

(“[A]ny presumption created by the doctrine of claim 

differentiation ‘will be overcome by a contrary construction dictated by the written description or prosecution 

history.’” (quoting Seachange Int’l, Inc. v. C-COR, Inc., 
12 FENNER INVESTMENTS, LTD. v. CELLCO PARTNERSHIP

413 F.3d 1361, 1369 (Fed. Cir. 2005))); Toro Co. v. White 

Consol. Indus., Inc., 199 F.3d 1295, 1302 (Fed. Cir. 1999)

(“[T]he doctrine of claim differentiation does not serve to 

broaden claims beyond their meaning in light of the 

specification, and does not override clear statements of 

scope in the specification and the prosecution history.” 

(citation omitted)). 

CONCLUSION

We discern no error in the district court’s claim construction, and affirm the summary judgment of noninfringement based thereon. 

AFFIRMED