  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, Wash-
ington, DC, argued for defendant-appellee. Also repre-
sented 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 Partner-
ship, doing business as Verizon Wireless, does not in-
fringe 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 sys-
tems, call servicing and billing were specific to a particu-
lar 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 servic-
ing 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 identifi-
cation numbers such that billing and connecting proce-
dures may be accomplished” in order to realize the
benefits of uncoupling devices and individual users oper-
ating 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 num-
bers 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 bill-
   ing authorities for maintaining service profiles of
   mobile users and a plurality of location authori-
   ties 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 communica-
       tion 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 au-
       thorities 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 re-
       ceived 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 identifica-
tion 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 defini-
tion, 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 histo-
ry.”). 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 prosecu-
tion history. Phillips v. AWH Corp., 415 F.3d 1303, 1312–
1317 (Fed. Cir. 2005) (en banc). Any explanation, elabo-
ration, 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 inven-
tion” that is disclosed, described, and patented. Retracta-
ble Techs., Inc. v. Becton, Dickinson & Co., 653 F.3d 1296,
1305 (Fed. Cir. 2011).
    Words are symbols, linguistic embodiments of infor-
mation 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 Instru-
ments, 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 tech-
nology, 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 under-
standing 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 com-
munications unit or physical location but are associated
with individual users.” ’706 Patent col. 2 ll. 30-36. Veri-
zon argues that this description limits the available scope
of claim 1. See, e.g., Verizon Servs. Corp. v. Vonage Hold-
ings 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 associat-
ed with the telephones present in a household or busi-
ness” 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 indi-
vidual 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 identi-
fication 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 person-
   al 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 loca-
    tions . . . 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 fur-
ther demonstrates that the ’706 patent is for a user-
centered 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 num-
ber” 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 infor-
mation 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 equiva-
lent 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, as-
signed to a particular home exchange.” J.A. 2509.
     Fenner argues that these purportedly limiting state-
ments 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 construc-
tion of “personal identification number” to mean “associ-
ated with the individual and not the device” cannot be
correct because it renders the patented invention inoper-
able. Fenner states that only a device (not a person) is
capable of transmitting the personal identification num-
ber 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 construc-
tion means that “there can never be any association
between the personal identification number and the
device” and, thus, is incorrect. Appellant Br. 28. Howev-
er, the district court’s construction requires only that a
personal identification number is not permanently associ-
ated with a specific communications unit or location. This
construction is not flawed.
                 D. Claim Differentiation
    Fenner also argues that the doctrine of claim differen-
tiation 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 identifi-
     cation code wherever that user is located within
     the communications network, a method for com-
     pleting a call from a source to a destination user
     comprising:
     receiving from a source user logged onto a first
         communication switch a personal identifica-
         tion code of a destination user to whom a call
         is to be routed:
     determining whether the destination user is cur-
         rently 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 as-
            signed to the personal identification code
            of the destination user,
        requesting from the location tracking authori-
            ty an identity for a destination communi-
            cation switch on which the destination
            user is currently logged onto,
        receiving the identity of the destination com-
            munication switch at the first communica-
            tion 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 inde-
pendent 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 differenti-
ation 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 limita-
tion in Claim 19 would have been unnecessary.” Appel-
lant 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 construc-
tion 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 con-
struction, and affirm the summary judgment of nonin-
fringement based thereon.
                      AFFIRMED
