 United States Court of Appeals
     for the Federal Circuit
            ______________________

  COX COMMUNICATIONS, INC., COXCOM, LLC,
       COX ARKANSAS TELCOM LLC, COX
COMMUNICATIONS ARIZONA LLC, COX ARIZONA
 TELCOM LLC, COX CALIFORNIA TELCOM LLC,
COX COMMUNICATIONS CALIFORNIA LLC, COX
 COLORADO TELCOM LLC, COX CONNECTICUT
  TELCOM LLC, COX DISTRICT OF COLUMBIA
 TELCOM LLC, COX FLORIDA TELCOM LP, COX
     COMMUNICATIONS GEORGIA LLC, COX
GEORGIA TELCOM LLC, COX IOWA TELCOM LLC,
          COX IDAHO TELCOM LLC, COX
 COMMUNICATIONS KANSAS LLC, COX KANSAS
  TELCOM LLC, COX COMMUNICATIONS GULF
COAST LLC, COX COMMUNICATIONS LOUISIANA
     LLC, COX LOUISIANA TELCOM LLC, COX
    MARYLAND TELCOM LLC, COX MISSOURI
  TELCOM LLC, COX NEBRASKA TELCOM LLC,
    COX COMMUNICATIONS OMAHA LLC, COX
    COMMUNICATIONS LAS VEGAS INC., COX
 NEVADA TELCOM LLC, COX NORTH CAROLINA
   TELCOM LLC, COX OHIO TELCOM LLC, COX
 OKLAHOMA TELCOM LLC, COX RHODE ISLAND
      TELCOM LLC, COX COMMUNICATIONS
HAMPTON ROADS, LLC, COX VIRGINIA TELCOM
                       LLC,
                Plaintiffs-Appellees

                      v.

   SPRINT COMMUNICATION COMPANY LP,
 SPRINT SPECTRUM, L.P., SPRINT SOLUTIONS,
                  INC.,
2       COX COMMUNICATIONS, INC.   v. SPRINT COMMUNICATION
                                                  COMPANY


                  Defendants-Appellants

                CISCO SYSTEMS, INC.,
                       Defendant
                 ______________________

                       2016-1013
                 ______________________

    Appeal from the United States District Court for the
District of Delaware in No. 1:12-cv-00487-SLR, Judge Sue
L. Robinson.
                 ______________________

              Decided: September 23, 2016
                ______________________

    MICHAEL LOUIS BRODY, Winston & Strawn LLP, Chi-
cago, IL, argued for plaintiffs-appellees. Also represented
by STEFFEN NATHANAEL JOHNSON, EIMERIC REIG-PLESSIS,
Washington, DC; DAVID SPENCER BLOCH, San Francisco,
CA; KRISHNAN PADMANABHAN, New York, NY.

    J. MICHAEL JAKES, Finnegan, Henderson, Farabow,
Garrett & Dunner, LLP, Washington, DC, argued for
defendants-appellants. Also represented by BASIL TRENT
WEBB, PETER EMANUEL STRAND, AARON E. HANKEL, JOHN
D. GARRETSON, RYAN DYKAL, Shook, Hardy & Bacon, LLP,
Kansas City, MO; ROB RECKERS, Houston, TX.
                ______________________

Before PROST, Chief Judge, NEWMAN and BRYSON, Circuit
                       Judges.
    Opinion for the court filed by Chief Judge PROST.
Opinion concurring in the judgment filed by Circuit Judge
                        NEWMAN.
COX COMMUNICATIONS, INC.   v. SPRINT COMMUNICATION         3
COMPANY


PROST, Chief Judge.
     Sprint Communication Company LP and its affiliates
(collectively, “Sprint”) appeal from a final decision of the
United States District Court for the District of Delaware
finding that the asserted claims of U.S. Patent Nos.
6,452,932; 6,463,052; 6,633,561; 7,286,561; 6,298,064; and
6,473,429 (collectively, “the asserted patents”) are invalid
as indefinite under 35 U.S.C. § 112, ¶ 2. Because “pro-
cessing system” does not prevent the claims, read in light
of the specification and the prosecution history, from
informing those skilled in the art about the scope of the
invention with reasonable certainty, we reverse.
                       BACKGROUND
    The asserted patents relate to developments in voice-
over-IP technology. Voice-over-IP allows telephone calls
to be transmitted over the internet, instead of through
traditional telephone lines. Voice-over-IP has the ability
to work with traditional telephone lines, however, such
that calls initiated on a traditional telephone can be
converted to packets of information and transmitted over
the internet. At the receiving end, they are converted
back to a traditional voice signal.
     The asserted patents discuss the hand-off between
traditional telephone lines (a “narrow-band network” or
“circuit-switched network”) and a data network (a “broad-
band network” or “packet-switched network”), such as the
internet. They can be divided into two groups: U.S.
Patent Nos. 6,452,932 (“’932 patent”); 6,463,052 (“’052
patent”); 6,633,561 (“’3,561 patent”); and 7,286,561
(“’6,561 patent”) (collectively, the “control patents”) share
a specification, and U.S. Patent Nos. 6,298,064 (“’064
patent”) and 6,473,429 (“’429 patent”) (collectively, the
4       COX COMMUNICATIONS, INC.    v. SPRINT COMMUNICATION
                                                    COMPANY


“ATM 1 interworking patents”) share a different specifica-
tion.
     Both sets of patents describe the use of a “processing
system,” which receives a signal from a traditional tele-
phone network and processes information related to that
voice call to select the path that the voice call should take
through the data network. In the control patents, a
“communications control processor” (“CCP”) “selects the
network elements and the connections that comprise the
communications path.” ’3, 561 patent col. 6 ll. 18–20. In
the ATM interworking patents, a “signaling processor”
(or, in preferred embodiments, a “call/connection manag-
er” (“CCM”)) selects the virtual connections by which the
call will pass through the ATM network and performs
other call processing functions, such as validation, echo
control, and billing. ’064 patent col. 4 ll. 47–54, col. 6 ll.
54–59, col. 7 ll. 13–16. Both specifications disclose that
logic for selecting a communication path resides in look-
up-tables, which the CCP or CCM relies on in making
selection(s). ’3, 561 patent col. 19 ll. 1–27, col. 19 l. 33–
col. 20 l. 6; ’064 patent col. 7 ll. 21–30.
    At issue in this appeal is the definiteness of “pro-
cessing system” as it is used in the context of the patents.
Among the control patents, the independent claims at
issue are: claim 1 of the ’932 patent, claim 1 of the ’052
patent, claims 1 and 24 of the ’3,561 patent, and claim 11
of the ’6,561 patent. Claim 1 of the ’3, 561 patent is
exemplary:
    1. A method of operating a processing system to
    control a packet communication system for a user
    communication, the method comprising:



    1   “ATM” stands for “Asynchronous Transfer Mode,”
which is a certain type of broadband network that can be
used in voice-over-IP systems.
COX COMMUNICATIONS, INC.   v. SPRINT COMMUNICATION       5
COMPANY


   receiving a signaling message for the user com-
   munication from a narrowband communication
   system into the processing system;
   processing the signaling message to select a net-
   work code that identifies a network element to
   provide egress from the packet communication
   system for the user communication;
   generating a control message indicating the net-
   work code;
   transferring the control message from the pro-
   cessing system to the packet communication sys-
   tem;
   receiving the user communication in the packet
   communication system and using the network
   code to route the user communication through the
   packet communication system to the network el-
   ement; and
   transferring the user communication from the
   network element to provide egress from the pack-
   et communication system.
’3, 561 patent col. 22 ll. 12–32 (emphases added).
    Among the ATM interworking patents, claim 1 of the
’064 patent and claim 1 of the ’429 patent are the inde-
pendent claims at issue. Claim 1 of the ’064 patent is
exemplary:
   1. A communication method for a call comprising:
   receiving set-up signaling associated with the call
   into a processing system;
   processing the set-up signaling in the processing
   system to select a DS0 connection;
   generating a message identifying the DS0 connec-
   tion;
6       COX COMMUNICATIONS, INC.    v. SPRINT COMMUNICATION
                                                     COMPANY


    transmitting the message from the processing sys-
    tem;
    receiving the message and an asynchronous com-
    munication associated with the call into an inter-
    working unit;
    in the interworking unit, converting the asyn-
    chronous communication into a user communica-
    tion; and
    transferring the user communication from the in-
    terworking unit to the DS0 connection in response
    to the message.
’064 patent col. 23 ll. 28–41 (emphases added).
                   PROCEDURAL HISTORY
     This case rests against the backdrop of multi-district
litigation between these parties and others. On December
19, 2011, Sprint sued Cox Communications, Inc. and Cox
Communications Kansas, LLC in the District of Kansas,
asserting infringement of twelve patents, which included
the six patents at issue here. That same day, Sprint also
filed suit against Comcast Cable Communications, Inc.
(“Comcast”), Cable One, Inc. (“Cable One”), and Time
Warner Cable Inc. (“Time Warner Cable”) in the District
of Kansas asserting the same twelve patents.
    On April 16, 2012, Cox Communications, Inc., Cox
Communications Kansas, LLC, and thirty of their affili-
ates (collectively, “Cox”) initiated the instant case, filing a
complaint in the District of Delaware seeking declaratory
judgment that Sprint’s twelve patents were invalid and
not infringed. Cox filed a motion to transfer the Kansas
action to Delaware, which was granted on September 14,
2012. Sprint consequently counterclaimed for infringe-
ment of the twelve patents and several others.
   Sprint’s actions against Comcast, Cable One, and
Time Warner Cable remained in the District of Kansas
COX COMMUNICATIONS, INC.   v. SPRINT COMMUNICATION        7
COMPANY


and were consolidated for discovery purposes. These
cases proceeded to claim construction, where on October
9, 2014, the district court decided, among other things,
that the term “processing system” was not indefinite, but
did not warrant a construction. J.A. 838–41.
    Approximately four months later, on February 27,
2015, Cox moved for partial summary judgment in the
instant case on the grounds that the claim term “pro-
cessing system” rendered the asserted patents indefinite
under 35 U.S.C. 112, ¶ 2. On May 15, 2015, the district
court granted Cox’s motion, finding that the claims were
indefinite because they “contain[] a structural limitation,
‘processing system,’” which is “functionally described by
the claims and in the specifications” and these descrip-
tions “do not pass muster under Nautilus as a person of
ordinary skill in the art is not provided with the bounds of
the claimed invention.” J.A. 17–19. The district court
also found that extrinsic evidence did not save the claims,
because “there is no ‘established meaning in the art’” for
“processing system,” because other patents use this term
in different ways and because the parties did not provide
(nor could the district court discern, looking at computer
dictionaries) a definition for “processing system.” J.A. 19.
    Sprint appeals the grant of summary judgment of in-
validity for indefiniteness. We have jurisdiction under 28
U.S.C. § 1295(a)(1).
                       DISCUSSION
    We review a district court’s grant of summary judg-
ment that a claim is indefinite de novo, applying the same
standards as the district court. Ethicon Endo-Surgery,
Inc. v. U.S. Surgical Corp., 149 F.3d 1309, 1315 (Fed. Cir.
1998). The ultimate conclusion that a claim is indefinite
8       COX COMMUNICATIONS, INC.   v. SPRINT COMMUNICATION
                                                   COMPANY


under 35 U.S.C. § 112, ¶ 2 2 is a legal conclusion, which we
review de novo. Eidos Display, LLC v. AU Optronics
Corp., 779 F.3d 1360, 1364 (Fed. Cir. 2015). As in claim
construction, we review a district court’s underlying
factual determinations for clear error. Id.; see Teva
Pharm. USA, Inc. v. Sandoz, Inc., 135 S. Ct. 831, 840
(2015). “Any fact critical to a holding on indefinite-
ness . . . must be proven by the challenger by clear and
convincing evidence.” Intel Corp. v. VIA Techs., Inc., 319
F.3d 1357, 1366 (Fed. Cir. 2003). If indefiniteness can be
determined based solely on intrinsic evidence, our review
is de novo. See Teva Pharm. USA, Inc., 135 S. Ct. at 840.
    At the outset, we note that the parties have agreed
that “processing system” is not a means-plus-function
term. J.A. 20, n.9. Accordingly, we confine our review to
the same question presented to the district court: whether
“processing system” renders the asserted patents indefi-
nite under 35 U.S.C. § 112, ¶ 2.
    Section 112 requires that “[t]he specification shall
conclude with one or more claims particularly pointing
out and distinctly claiming the subject matter which the
inventor or a joint inventor regards as the invention.” 35
U.S.C. § 112, ¶ 2. This provision strikes a “delicate bal-
ance” which recognizes that, although the definiteness
requirement must tolerate “[s]ome modicum of uncertain-
ty” as “the price of ensuring the appropriate incentives for
innovation,” Nautilus, Inc. v. Biosig Instruments, Inc., 134
S. Ct. 2120, 2128–29 (2014) (quoting Festo Corp. v. Sho-
ketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722, 731


    2   The America Invents Act (AIA), Pub. L. No. 112–
29, effective September 16, 2012, has newly designated
§ 112, ¶ 2 as § 112(b) and § 112, ¶ 6 as § 112(f). Because
the asserted patents stem from applications that were
filed before the effective date of the AIA, we will refer to
the pre-AIA versions of these provisions.
COX COMMUNICATIONS, INC.   v. SPRINT COMMUNICATION          9
COMPANY


(2002)) (internal quotation marks omitted), a patent must
nevertheless “be precise enough to afford clear notice of
what is claimed, thereby apprising the public of what is
still open to them.” Id. (quoting Markman v. Westview
Instruments, Inc., 517 U.S. 370, 373 (1996)) (internal
quotation marks omitted). Accordingly, “a patent is
invalid for indefiniteness if its claims, read in light of the
specification delineating the patent, and the prosecution
history, fail to inform, with reasonable certainty, those
skilled in the art about the scope of the invention.” Id. at
2129.
    This case presents a peculiar scenario: the sole source
of indefiniteness that Cox complains of, “processing sys-
tem,” plays no discernable role in defining the scope of the
claims. All of the asserted claims are method claims, and
the point of novelty resides with the steps of these meth-
ods, not with the machine that performs them. “Pro-
cessing system” is merely the locus at which the steps are
being performed. The plain language of the claims proves
this point: if claim 1 of the ’3,561 patent (which the par-
ties agree is exemplary for the control patents) were
revised to remove the word “processing system,” the
meaning would not discernably change:
10      COX COMMUNICATIONS, INC.   v. SPRINT COMMUNICATION
                                                 COMPANY



’3,561 patent, claim 1, ’3,561 patent, claim 1,
with “processing sys- without        “processing
tem”                    system”

1. A method of operating a     1. A method to control a
processing system to control   packet       communication
a packet communication         system for a user communi-
system for a user communi-     cation, the method compris-
cation, the method compris-    ing:
ing:
                             receiving a signaling mes-
receiving a signaling mes- sage for the user communi-
sage for the user communi- cation from a narrowband
cation from a narrowband communication system;
communication system into
                             processing the signaling
the processing system;
                             message to select a network
processing the signaling code that identifies a net-
message to select a network work element to provide
code that identifies a net- egress from the packet
work element to provide communication system for
egress from the packet the user communication;
communication system for
                             ...
the user communication;
                             transferring   the   control
...
                             message to the packet
transferring the control communication system
message from the pro-
                             ...
cessing system to the packet
communication system
...



This modification removes the clarification that the
“processing system” is what performs the “processing” and
receives and sends certain signals, but even without this
clarification, the same steps would have to be performed.
COX COMMUNICATIONS, INC.   v. SPRINT COMMUNICATION     11
COMPANY


(And, from the nature of the invention, they would have to
be performed on some kind of computing device.) The
same is true of claim 1 of the ’064 patent (which the
parties agree is exemplary for the ATM interworking
patents):



’064 patent, claim 1, with ’064 patent, claim 1,
“processing system”        without     “processing
                           system”

1. A communication method 1. A communication method
for a call comprising:    for a call comprising:
receiving set-up signaling receiving set-up signaling
associated with the call into associated with the call;
a processing system;
                              processing    the     set-up
processing     the    set-up signaling to select a DS0
signaling in the processing connection;
system to select a DS0
                              ...
connection;
                              transmitting the message;
...
                              ...
transmitting the message
from the processing system;
...



If “processing system” were not omitted but replaced with
“computer,” a similar conclusion results. Indeed, at oral
argument, both parties agreed that substituting “comput-
er” for “processing system” would not change the scope of
the claims. Oral Argument at 10:19–32, 14:57–15:05,
available                                               at
http://oralarguments.cafc.uscourts.gov/default.aspx?fl=20
16-1013.mp3 [hereinafter Oral Argument]; see also Oral
12       COX COMMUNICATIONS, INC.   v. SPRINT COMMUNICATION
                                                   COMPANY


Argument at 11:55–12:18, 14:42–14:57 (acknowledging
that “processing system” is a general purpose computer).
    If “processing system” does not discernably alter the
scope of the claims, it is difficult to see how this term
would prevent the claims (the remainder of which Cox
does not challenge on indefiniteness grounds) from serv-
ing their notice function under § 112, ¶ 2. As Nautilus
instructs, the dispositive question in an indefiniteness
inquiry is whether the “claims,” not particular claim
terms, “read in light of the specification delineating the
patent, and the prosecution history, fail to inform, with
reasonable certainty, those skilled in the art about the
scope of the invention.” 3 134 S. Ct. at 2129. To be sure,
we have generally acknowledged that an indefiniteness
analysis under 35 U.S.C. § 112, ¶ 2 is “inextricably inter-
twined with claim construction.” Atmel Corp. v. Info.



     3  The concurrence adopts this same point at base,
agreeing that Nautilus provides “[t]he operative criterion”
for questions under § 112, ¶ 2. Concurring Op. at 6.
Nevertheless, it appears to take great issue with our
method of analysis, which it interprets as creating a “new
protocol” that hinges on “deleting the challenged term
from the claims.” Id. at 2, 6. Our opinion today does no
such thing. Rather, we compare versions of the claims
that contain and then exclude “processing system” simply
as a way of illustrating how Nautilus applies to the claims
at issue: Nautilus focuses on whether the “claims . . . fail
to inform,” 134 S. Ct. at 2129, and the comparison reveals
that this conclusion depends largely on the remainder of
the claim language, not the “processing system” term. It
follows then that, because it has little impact on this
ultimate question, it would be difficult for “processing
system” to be a source of indefiniteness. This conclusion
derives only from an application of Nautilus to the claims
at issue and invites no change to the law of § 112, ¶ 2.
COX COMMUNICATIONS, INC.   v. SPRINT COMMUNICATION         13
COMPANY


Storage Devices, Inc., 198 F.3d 1374, 1379 (Fed. Cir.
1999). Accordingly, the common practice of training
questions of indefiniteness on individual claim terms is a
helpful tool. Indeed, if a person of ordinary skill in the art
cannot discern the scope of a claim with reasonable cer-
tainty, it may be because one or several claim terms
cannot be reliably construed. See, e.g., Interval Licensing
LLC v. AOL, Inc., 766 F.3d 1364, 1374 (Fed. Cir. 2014)
(finding the phrase “unobtrusive manner” rendered claims
indefinite because, even after consulting the claims,
specification, and prosecution history, a skilled artisan
would be left “to consult the unpredictable vagaries of any
one person’s opinion”) (citations and internal quotation
marks omitted).       Nevertheless, indefiniteness under
§ 112, ¶ 2 must ultimately turn on the question set forth
by Nautilus: whether the “claims, read in light of the
specification delineating the patent, and the prosecution
history, fail to inform, with reasonable certainty, those
skilled in the art about the scope of the invention.” Id. at
2129 (emphasis added). Applied here, “processing sys-
tem” does not prevent the claims from doing just that.
    Cox nevertheless contends that “processing system” is
indefinite because the asserted claims only describe it in
functional terms. We disagree. Claims are not per se
indefinite merely because they contain functional lan-
guage. 4 See also Microprocessor Enhancement Corp. v.



    4   We note, however, that in the context of 35 U.S.C.
§ 112, ¶ 6, we require that, if a patentee writes his claims
in “means-plus-function” form, he must “disclose the
particular structure that is used to perform the recited
function.” Blackboard, Inc. v. Desire2Learn, Inc., 574
F.3d 1371, 1385 (Fed. Cir. 2009). This is intended to
avoid “pure functional claiming,” where a patentee
“claim[s] all possible means of achieving a function.” Id.
However, by agreeing that “processing system” is not a
14      COX COMMUNICATIONS, INC.   v. SPRINT COMMUNICATION
                                                   COMPANY


Tex. Instruments Inc., 520 F.3d 1367, 1375 (Fed. Cir.
2008) (citing Halliburton Energy Servs., Inc. v. M–I LLC,
514 F.3d 1244, 1255 (Fed. Cir. 2008)) (“[A]pparatus claims
are not necessarily indefinite for using functional lan-
guage”). Indeed, here, functional language promotes
definiteness because it helps bound the scope of the
claims by specifying the operations that the “processing
system” must undertake. All of the asserted claims are
method claims, so it makes sense to define the inventive
method as a series of functions.
    Further, Cox cannot complain that the specific func-
tional limitations that describe the operation of the “pro-
cessing system” in the asserted patents fail to provide
sufficient clarity under Nautilus. For example, in the
control patents, claim 1 of the ’3,561 patent requires that
the “method of operating a processing system . . . pro-
cess[es] the signaling message to select a network code
that identifies a network element to provide egress from
the packet communication system for the user communi-



means-plus-function term, Cox has already conceded that
“processing system” itself recites sufficiently definite
structure and there is no problem of “pure functional
claiming” here. See Williamson v. Citrix Online, LLC, 792
F.3d 1339, 1348 (Fed. Cir. 2015) (en banc) (“[W]hen a
claim term lacks the word ‘means,’ . . . § 112, para. 6 will
apply if the challenger demonstrates that the claim term
fails to ‘recite[] sufficiently definite structure’ or else
recites ‘function without reciting sufficient structure for
performing that function.’” (quoting Watts v. XL Sys., Inc.,
232 F.3d 877, 880 (Fed. Cir. 2000))). Indeed, the claims
specify that the claimed functions are achieved through
the use of the “processing system,” which the parties
agree is, as used in the context of the patents here, a
general purpose computer. Oral Argument at 11:55–
12:18, 14:42–14:57.
COX COMMUNICATIONS, INC.    v. SPRINT COMMUNICATION          15
COMPANY


cation.” The specification discloses, as an embodiment of
a “processing system,” the CCP and provides details about
how it functions to “select[] the network elements and the
connections that comprise the communications path.”
’3,561 patent col. 6 ll. 23–25. Notably, the specification
provides certain algorithmic details, including that “selec-
tions are made through table look-ups and SCP queries,”
id. at col. 14 ll. 45–48, and provides detail about how
these queries are constructed, see, e.g., id. at col. 14 ll. 49–
51, and the types of information that are used to deter-
mine these mappings, see, e.g., id. at col. 19 ll. 36–40.
These disclosures are sufficiently detailed such that,
reading claim 1 in light of the specification, a person of
ordinary skill in the art would understand claim 1’s
requirement that the “method of operating a processing
system . . . process[es] the signaling message to select a
network code . . .” with reasonable certainty.
    As another example, in the ATM interworking pa-
tents, claim 1 of the ’064 patent requires the step of
“processing the set-up signaling in the processing system
to select a DS0 connection.” In the specification, the ’064
patent discloses the CCM as an embodiment of a “pro-
cessing system” and provides details about how it “re-
ceive[s] and process[es] . . . signaling to select connections,
and to generate and transmit signaling identifying the
selections.” ’064 patent col. 6 ll. 57–59. Similar to the
specification of the control patents, the specification of the
’064 patent describes that “[t]he selection process can be
accomplished through table look-ups,” id., col. 7 ll. 20–21,
and provides detail about how the look-up process hap-
pens, see id. at col. 7 ll. 21–30. Accordingly, a person of
ordinary skill in the art would understand claim 1’s step
of “processing the set-up signaling in the processing
system to select a DS0 connection . . .” with reasonable
certainty.
    In sum, “processing system” does not render the
claims indefinite because it does not prevent the claims,
16      COX COMMUNICATIONS, INC.   v. SPRINT COMMUNICATION
                                                   COMPANY


read in light of the specification and the prosecution
history, from informing those skilled in the art about the
scope of the invention with reasonable certainty. Alt-
hough the asserted patents describe the operation of the
“processing system” in largely functional terms, the
recited steps, read in light of the specification, provide
sufficient detail such that a person of ordinary skill in the
art would understand them with reasonable certainty.
                       CONCLUSION
    For the foregoing reasons, we reverse the district
court’s conclusion that the term “processing system”
renders the asserted claims indefinite under § 112, ¶ 2.
                       REVERSED
 United States Court of Appeals
     for the Federal Circuit
            ______________________

  COX COMMUNICATIONS, INC., COXCOM, LLC,
       COX ARKANSAS TELCOM LLC, COX
COMMUNICATIONS ARIZONA LLC, COX ARIZONA
 TELCOM LLC, COX CALIFORNIA TELCOM LLC,
COX COMMUNICATIONS CALIFORNIA LLC, COX
 COLORADO TELCOM LLC, COX CONNECTICUT
  TELCOM LLC, COX DISTRICT OF COLUMBIA
 TELCOM LLC, COX FLORIDA TELCOM LP, COX
     COMMUNICATIONS GEORGIA LLC, COX
GEORGIA TELCOM LLC, COX IOWA TELCOM LLC,
          COX IDAHO TELCOM LLC, COX
 COMMUNICATIONS KANSAS LLC, COX KANSAS
  TELCOM LLC, COX COMMUNICATIONS GULF
COAST LLC, COX COMMUNICATIONS LOUISIANA
     LLC, COX LOUISIANA TELCOM LLC, COX
    MARYLAND TELCOM LLC, COX MISSOURI
  TELCOM LLC, COX NEBRASKA TELCOM LLC,
    COX COMMUNICATIONS OMAHA LLC, COX
    COMMUNICATIONS LAS VEGAS INC., COX
 NEVADA TELCOM LLC, COX NORTH CAROLINA
   TELCOM LLC, COX OHIO TELCOM LLC, COX
 OKLAHOMA TELCOM LLC, COX RHODE ISLAND
      TELCOM LLC, COX COMMUNICATIONS
HAMPTON ROADS, LLC, COX VIRGINIA TELCOM
                       LLC,
                Plaintiffs-Appellees

                      v.

   SPRINT COMMUNICATION COMPANY LP,
 SPRINT SPECTRUM, L.P., SPRINT SOLUTIONS,
                  INC.,
2       COX COMMUNICATIONS, INC.   v. SPRINT COMMUNICATION
                                                   COMPANY


                  Defendants-Appellants

                CISCO SYSTEMS, INC.,
                       Defendant
                 ______________________

                        2016-1013
                  ______________________

    Appeal from the United States District Court for the
District of Delaware in No. 1:12-cv-00487-SLR, Judge Sue
L. Robinson.
                 ______________________

NEWMAN, Circuit Judge, concurring in the judgment.
    I agree with the court’s holding that the claims are
not invalid on the ground of indefiniteness. However, the
court creates an interesting, but flawed, new mode of
analysis, whereby the adjudicator (1) first removes the
challenged term from the claim, then (2) decides whether
the claim has the same meaning without the challenged
term, and (3) if the answer is “yes,” rules that the claim is
not indefinite as a matter of law. Maj. Op. at 10–12. This
new style of claim construction will confound the already
confused determination of patent rights. I write to protest
this further inroad on a reasoned and reliable law of
patents.
    No precedent supports the court’s new protocol of
claim construction, whereby definiteness of the claim is
deemed proved because “if claim 1 of the ’3,561 pa-
tent . . . were revised to remove the term “processing
system,’ the meaning would not discernably change.”
Maj. Op. at 9. The court criticizes the parties for arguing
about the indefiniteness of “processing system” as result-
ing in a “peculiar scenario,” since, in the majority’s view,
the term “processing system,” despite its presence in three
COX COMMUNICATIONS, INC.   v. SPRINT COMMUNICATION         3
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clauses of claim 1 and other claims, “plays no discernable
role in defining the scope of the claims.” Id. However,
claim 1 is for a “method of operating a processing system”
by performing the six specified steps in the claim. This is
not a peculiar scenario.
    Cox argues that the term “processing system,” by its
asserted       indefiniteness,    “would      prevent    the
claims . . . from serving their notice function,” Maj. Op. at
12, based on the position that the term is not adequately
supported by structure. The district court so found. The
court today does not discuss this finding, instead simply
holding that definiteness is determined by removing the
challenged term from the claim in order to discover
whether the claim has the same construction without the
challenged term. I cannot discern how a claim can have
the same meaning and scope with and without a critical
term that limits three clauses of the claim. I show claim 1
of the ’3,561 patent, with boldface added to the usages of
“processing system”:
    1. A method of operating a processing system to
    control a packet communication system for a user
    communication, the method comprising:
    receiving a signaling message for the user com-
    munication from a narrowband communication
    system into the processing system;
    processing the signaling message to select a net-
    work code that identifies a network element to
    provide egress from the packet communication
    system for the user communication;
    generating a control message indicating the net-
    work code;
    transferring the control message from the pro-
    cessing system to the packet communication
    system;
4       COX COMMUNICATIONS, INC.   v. SPRINT COMMUNICATION
                                                   COMPANY


    receiving the user communication in the packet
    communication system and using the network
    code to route the user communication through the
    packet communication system to the network el-
    ement; and
    transferring the user communication from the
    network element to provide egress from the pack-
    et communication system.
’3,561 patent, claim 1 (emphases added).
    I agree with the panel majority that the use of func-
tional terms is not an automatic badge of invalidity, and
that the context, specification, and knowledge in the art
must be considered. My concern is with the court’s meth-
od of analysis. Functional terms in patents are not pro-
hibited, but they must meet the statutory requirements,
including:
    35 U.S.C. §112(a) In general.— The specification
    shall contain a written description of the inven-
    tion, and of the manner and practice of making
    and using it, in such full clear, concise, and exact
    terms as to enable an person skilled in the art to
    which it pertains . . . to make and use the same,
    and shall set forth the best mode contemplated by
    the inventor . . . of carrying out the invention.
    (b) Conclusion.— The specification shall conclude
    with one or more claims particularly pointing out
    and distinctly claiming the subject matter which
    the inventor . . . regards as the invention.
    Here the patentee claimed a method of operating a
processing system, comprising six steps. The court’s new
analytical method, whereby the challenged term is re-
moved from the claim and the court then decides whether
the claim is of the same meaning and scope, Maj. Op. at
COX COMMUNICATIONS, INC.   v. SPRINT COMMUNICATION          5
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10–11, is neither legally correct nor plausible. 1 I urge the
court to return to the traditional method of claim analy-
sis.
     Under traditional claim analysis, I agree that the
claims presented for review are not invalid on the ground
of indefiniteness. The evidentiary record supports the
conclusion that “processing system” had an understood
meaning within the telecommunications industry, and the
expert testimony and publications support the meaning as
a “system that processes signaling to assist in call con-
trol,” Declaration of Stephen B. Wicker, Ph.D, at 32 (J.A.
989), and that it would be so understood by persons
having ordinary skill in this field, Supplemental Wicker
Declaration at 4 (J.A. 997).
    The district court ruled that “processing system” is
indefinite because of insufficient disclosure of the struc-
ture that performs each claim step. The district court
stated that the physical structures were only “functionally
described by the claims and in the specifications,” that
they did not provide “a person of ordinary skill in the
art . . . with the bounds of the claimed invention,” and




    1   I take note that the court, while agreeing with the
parties that the claims before us are not in means-plus-
function form, nonetheless misapplies that law in stating
that “by agreeing that ‘processing system’ is not a means-
plus-function term, Cox has already conceded that ‘pro-
cessing system’ itself recites sufficiently definite structure
and there is no problem of ‘pure functional claiming’
here.” Maj. Op. at 13–14 n.4. However, agreeing that
“processing system” is not in means-plus-function form is
not a concession of structural support. Support is subject
to analysis on the facts of the particular case, as for every
invention.
6       COX COMMUNICATIONS, INC.   v. SPRINT COMMUNICATION
                                                   COMPANY


thus did “not pass muster under Nautilus.” Dist. Ct. Op.
at 9–10.
     The Nautilus question is whether “a patent’s claims,
viewed in light of the specification and prosecution histo-
ry, inform those skilled in the art about the scope of the
invention with reasonable certainty.” Nautilus, Inc. v.
Biosig Instruments, Inc., 134 S. Ct. 2120, 2129 (2014).
The district court stopped short, for this court has elabo-
rated that even for apparatus claims the “recitation
of . . . function” is “highly relevant to ascertaining the
boundaries” of a claim. Biosig Instruments, Inc. v. Nauti-
lus, Inc., 783 F.3d 1374, 1383 (Fed. Cir. 2015). We ex-
plained that the “claim language, specification, and
figures” should “provide sufficient clarity to skilled arti-
sans as to the bounds of the disputed term.” Id. at 1382-
83. The district court here focused inappropriately on
structural limits, whereas these limitations are all steps
in a method, not an apparatus. The operative criterion is
whether the claim, read in light of the specification and
prosecution history, informs skilled artisans of the scope
of the invention with reasonable certainty. Nautilus, 134
S. Ct. at 2129. Judicial determination of compliance with
this requirement is not achieved by deleting the chal-
lenged term from the claims. 2
    When method claims include functional limitations,
the claims must meet the statutory requirements, includ-
ing specificity and enablement. There is extensive prece-
dent, in a variety of factual situations, guiding the
analysis of whether the claim, viewed as a whole, “partic-
ularly point[s] out and distinctly claim[s] the subject


    2   The Majority states that it “does no such thing,”
Maj. Op. at 12 n. 3, although the deletions from the claims
are highlighted on two pages of diagrams “omit[ing]” the
term, id. at 11, without guidance as to limits, standards,
and reasoning.
COX COMMUNICATIONS, INC.   v. SPRINT COMMUNICATION         7
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matter which the inventor or a joint inventor regards as
the invention.” 35 U.S.C. § 112(b). The inquiry “focuses
on whether those skilled in the art would understand the
scope of the claim when the claim is read in light of the
rest of the specification.” Energizer Holdings, Inc. v. Int’l
Trade Comm’n, 435 F.3d 1366, 1370 (Fed. Cir. 2006).
    Sprint points to the description in the specification, as
support for the definiteness of the claimed processing
system. The specification states that the processing
system “comprises an interface that is external to the
Switches,” ’3,561 Patent at 3:53–56, with a signaling
translator, a processor, and associated memory for pro-
cessing information to select network characteristics.
’3,561 Patent at 14:16–20 and FIG. 4. The patents de-
scribe various known call processing systems in the prior
art and explain how the claimed system physically con-
nects to various telecommunications systems such as
Signal Transfer Points, switches, and Service Control
Points. Flow charts in the specification show interfaces
and connections, links to other devices and switches and
operational control systems, and transfers of signals. It is
noteworthy that Cox does not challenge the individual
claim steps but concentrates on the overall reference to
“processing system.”
    The evidentiary record and the law lead to the conclu-
sion that the claims were not proved invalid on the
ground of indefiniteness. 3 Although my colleagues today
reach the correct result, their analytical path is not in
accordance with law and should be rejected.




    3   This appeal was taken under Rule 54(b), thus, no
other issues are before the court, as to either validity or
infringement.
