        NOTE: This disposition is nonprecedential.


  United States Court of Appeals
      for the Federal Circuit
                 ______________________

   SPRINT COMMUNICATIONS COMPANY, L.P.,
              Plaintiff-Appellee

                            v.

  TIME WARNER CABLE, INC., TIME WARNER
 CABLE, LLC, TIME WARNER ENTERTAINMENT
        COMPANY, L.P., TIME WARNER
   ENTERTAINMENT-ADVANCE/NEWHOUSE
 PARTNERSHIP, TWC COMMUNICATIONS, LLC,
TIME WARNER CABLE INFORMATION SERVICES
                (KANSAS), LLC,
              Defendants-Appellants
             ______________________

                       2017-2247
                 ______________________

    Appeal from the United States District Court for the
District of Kansas in No. 2:11-cv-02686-JWL, Judge John
W. Lungstrum.
                 ______________________

           OPINION ISSUED: November 30, 2018
           OPINION MODIFIED: March 18, 2019 *
                 ______________________


   *   This opinion has been modified and reissued fol-
lowing a petition for en banc rehearing filed by appellants.
2    SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,
                                                    INC.


     J. MICHAEL JAKES, Finnegan, Henderson, Farabow,
Garrett & Dunner, LLP, Washington, DC, argued for plain-
tiff-appellee. Also represented by KATHLEEN DALEY, JASON
LEE ROMRELL; ROB RECKERS, Shook, Hardy & Bacon, LLP,
Houston, TX; RYAN DYKAL, JOHN D. GARRETSON, BASIL
TRENT WEBB, Kansas City, MO.

    JOHN C. O'QUINN, Kirkland & Ellis LLP, Washington,
DC, argued for defendants-appellants. Also represented by
MATTHEW PHILIP DOWNER, NATHAN S. MAMMEN, JASON M.
WILCOX; DAVID BENYACAR, DANIEL REISNER, Arnold & Por-
ter Kaye Scholer LLP, New York, NY; RON E. SHULMAN,
Latham & Watkins LLP, Menlo Park, CA; GABRIEL BELL,
LAWRENCE J. GOTTS, Washington, DC.

    WILLIAM F. LEE, Wilmer Cutler Pickering Hale and
Dorr LLP, Boston, MA, for amici curiae Intel Corporation,
Dell Inc. Also represented by CHRISTOPHER D. DODGE,
MARK CHRISTOPHER FLEMING, LAUREN B. FLETCHER. Ami-
cus curiae Intel Corporation also represented by MATTHEW
JOHN HULT, Intel Corporation, Santa Clara, CA. Amicus
curiae Dell Inc. also represented by THOMAS A. BROWN,
KRISHNENDU GUPTA, Dell Inc., Hopkington, MA.
                  ______________________

    Before CHEN, MAYER, and BRYSON, Circuit Judges.
    Opinion for the court filed by Circuit Judge BRYSON.
     Dissenting opinion filed by Circuit Judge MAYER.
BRYSON, Circuit Judge.
    This patent infringement case was brought by Sprint
Communications Company, L.P. (“Sprint”) against Time
Warner Cable, Inc., and several of its affiliates (collec-
tively, “Time Warner”) in the United States District Court
for the District of Kansas. Sprint is the owner of the five
patents-in-suit: U.S. Patent Nos. 6,298,064 (“the ’064 pa-
tent”); 6,343,084 (“the ’084 patent”); 6,463,052 (“the ’052
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,        3
INC.


patent”); 6,473,429 (“the ’429 patent”); and 6,633,561 (“the
’561 patent”). Following trial, the jury found all five pa-
tents infringed and returned a verdict of approximately
$140 million in Sprint’s favor. We affirm.
                              I
     The technology at issue in this case involves methods
for linking circuit-switched and packet-switched networks
within a telecommunications system. The invention at the
heart of the patents in suit is a method for using a packet-
switched network to transport telephone calls and data to
and from the existing circuit-switched network for tele-
phone communications known as the Public Switched Tel-
ephone Network (“PSTN”).           The inventions allowed
telephone calls and data to be transmitted between those
two different networks seamlessly.
     The traditional PSTN used circuit switching to set up
an end-to-end path for each call. In a circuit-switched net-
work, a user’s telephone connects to a switch, and the
switch determines, based on the dialed number, which
switch will be selected as the next switch in the path. That
process continues switch-by-switch until the switch that is
connected to the called party is reached. The signaling be-
tween the switches establishes a fixed circuit for the entire
call, and the call occupies the entire bandwidth of that cir-
cuit for the duration of the call.
    The traditional circuit-switched technology works well
for voice communications, but less well for data communi-
cation. Because data communication tends to come in
bursts rather than as a continuous transmission of infor-
mation, the use of a fixed circuit for data transmission can
be wasteful of bandwidth during periods in which data is
not being transmitted but the circuit remains active. Ac-
cordingly, communications companies developed packet-
based solutions to increase the efficiency of data communi-
cations. Two types of packet-based technology that are per-
tinent to this case emerged: (1) asynchronous transfer
4   SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,
                                                   INC.


mode technology (“ATM”), which used “virtual circuits”
that established fixed routes for communications but ena-
bled multiple users to share the circuits at the same time;
and (2) internet protocol (“IP”) technology, in which each
IP router in an IP network would make an individual rout-
ing decision for each packet based on the ultimate destina-
tion of the packet. In the IP system, individual packets
that are part of a single communication can travel different
paths to the same destination.
     The patents at issue in this case fall into two groups:
the “call control” patents (the ’052 and ’561 patents) and
the “broadband” patents (the ’064, ’084, and ’429 patents).
The call control patents describe methods for telecommu-
nication control of calls to and from the packet-switched
communication network. The broadband patents address
the interface between circuit-switched (or “narrowband”)
networks and packet-switched (or “broadband”) networks.
Sprint accused Time Warner of infringing the call control
and broadband patents by using a Voice over Internet Pro-
tocol (“VoIP”) service, which converted calls into packet
data, transmitted the call over an IP network, and provided
for connectivity to the PSTN.
                              II
        A. THE ADMISSION OF THE VONAGE VERDICT
    Time Warner’s first contention on appeal is that the
district court improperly permitted Sprint to introduce ev-
idence relating to the jury verdict in an earlier, related case
brought by Sprint against Vonage, another carrier offering
VoIP service. That case involved the same technology that
was at issue in this case and resulted in a damages award
against Vonage. Time Warner contends that the admission
of the evidence relating to the Vonage verdict prejudiced it
and requires that it be granted a new trial.
    The district court ruled that the Vonage evidence was
relevant to the jury’s assessment of reasonable royalty
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,        5
INC.


damages under a hypothetical negotiation theory. The
court gave the jury an instruction limiting the use of that
evidence to the jury’s consideration of the issues of dam-
ages and willfulness.
    Although Time Warner argues that the introduction of
evidence of a jury verdict from another case is invariably
improper, that is not the rule that this court has applied.
Instead, the court has held that such evidence can be ad-
missible if it is relevant for some legitimate purpose.
    In Applied Medical Resources Corp. v. U.S. Surgical
Corp., 435 F.3d 1356 (Fed. Cir. 2006), this court affirmed
the admission of evidence regarding a prior verdict be-
tween the parties on the ground that the evidence of that
verdict was relevant to the hypothetical negotiation be-
tween the same parties, which bore on the amount of the
damages to be awarded under a reasonable royalty theory
of damages, as well as the issue of willfulness. Id. at 1365–
66. As to the relevance of the prior verdict on the issue of
damages, the court held that the verdict “was relevant to
the reasonable royalty analysis because the hypothetical
negotiation in 1997 took place on the heels of the [prior]
jury verdict.” Id. at 1366. The court added that the appel-
lant failed to show that the probative value of the evidence
was outweighed by the danger of unfair prejudice. Id.
    The Applied Medical Resources case applied a flexible
approach to the admission of evidence of prior verdicts or
other proceedings. 1 While such evidence can be prejudicial



    1   In its effort to distinguish Applied Medical Re-
sources, Time Warner alludes to the fact that the earlier
verdict in that case was against the same defendant. But
that factor would seem to make the risk of prejudice
stronger, not weaker, as the court explained in Coleman
Motor Co. v. Chrysler Corp., 525 F.2d 1338, 1351 (3d Cir.
1975), a case on which Time Warner heavily relies.
6   SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,
                                                   INC.


and must be treated with great care, it is admissible if it is
relevant to a material issue in the case and its use is lim-
ited to the purpose for which it is relevant. See Mendenhall
v. Cedarapids, Inc., 5 F.3d 1557, 1573–74 (Fed. Cir. 1993)
(evidence of prior litigation “must pass muster, like any
other evidence, as relevant and probative of an issue in the
second case”). 2
    In this case, the court admitted the prior verdict evi-
dence as relevant to willfulness, to Time Warner’s equita-
ble defenses, and “to the extent that it informs Sprint’s
executives concerning what [they] might expect as a rea-
sonable royalty.” Thus, as the court explained, the verdict
would be a factor of which the parties would have been
aware at the time of their hypothetical negotiation in 2010,
and a reasonable jury could well conclude that the verdict
and the amount of damages awarded in a similar prior




    2    While Time Warner cites several cases that have
disapproved of the admission of evidence regarding the out-
come of earlier cases, none of those cases is persuasive au-
thority as applied to the circumstances of this case. In
Engquist v. Oregon Department of Agriculture, 478 F.3d
985, 1008–09 (9th Cir. 2007), the court held that the dis-
trict court did not abuse its discretion by excluding evi-
dence of the outcome of a prior proceeding, while noting
that such evidence is admissible if it is relevant to an issue
in the later case and is not unfairly prejudicial. In Olitsky
v. Spencer Gifts, Inc., 964 F.2d 1471, 1475–76 (5th Cir.
1992), the court held that the evidence of the outcome of
prior litigation was relevant and that any prejudice was
cured by an appropriate limiting instruction. Finally, as
noted, in Coleman Motor Co., the prior verdict was against
the same defendant, and the court observed that a jury “is
likely to give a prior verdict against the same defendant
more weight than it warrants.” 525 F.2d at 1351.
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,        7
INC.


litigation would have influenced the outcome of a hypothet-
ical negotiation in the case at bar.
    Importantly, the district court gave the jury limiting
instructions that the Vonage evidence was to be considered
only on the issues of damages and willfulness. The court
gave such an instruction at Time Warner’s request both
times evidence of the Vonage verdict was introduced and in
the court’s final jury charge. While the court might have
given an even more restrictive instruction, no request was
made for such a further limitation on the instruction given
to the jury.
    Time Warner argues that the differences between the
Vonage case and this case were such that the district court
should have excluded the Vonage evidence on relevance
grounds. We disagree. While there are some differences
between the two proceedings, the core allegations in both
were the same. And while Time Warner argues that there
were several patents raised in each case that were not
raised in the other, Time Warner has not shown in its briefs
any reason to believe that the technology asserted in the
Vonage case was materially different from the technology
raised in this case. Any differences between the two pro-
ceedings, moreover, were available to Time Warner to ar-
gue to the jury; the differences did not require exclusion of
the Vonage verdict.
     As for Time Warner’s contention that Sprint’s counsel
made inflammatory use of the prior verdict before the jury,
we find that argument to be overstated. The references to
the jury verdict about which Time Warner complains were
made in the context of a discussion of the hypothetical ne-
gotiation. Several of the references were made in Sprint’s
opening statement. No objection was raised to those re-
marks as exceeding the limited grounds on which the dis-
trict court permitted the Vonage evidence to be used. In
closing argument, Sprint’s counsel again referred to the
Vonage verdict as it bore on the hypothetical negotiation
8   SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,
                                                   INC.


issue and on the issue of willfulness, as the district court
had permitted. Having examined each of counsel’s refer-
ences to the prior verdict, as well as the evidence regarding
the Vonage verdict that was introduced at trial, we are sat-
isfied that counsel did not make improper or inflammatory
use of the Vonage evidence, and that the district court did
not commit reversible error in failing to strike that evi-
dence or prohibit it from being offered for any purpose.
                 B. THE DAMAGES AWARD
    The jury assessed damages against Time Warner in the
amount of $1.37 per VoIP subscriber per month. Time
Warner complains that the district court erred in several
respects in handling the issue of damages.
    First, Time Warner contends that, for the same reasons
that Time Warner objected to the admission of evidence of
the Vonage verdict, the damages award should be over-
turned because Sprint’s damages expert relied on that ver-
dict in calculating a reasonable royalty.
     In addition to the previously raised objections to the
admission of evidence of the Vonage verdict, Time Warner
argues that the use of the Vonage verdict in the expert’s
damages calculation was improper because the Vonage ver-
dict was legally flawed. Time Warner argues that Sprint’s
expert in the Vonage case improperly relied in part on the
25 percent “rule of thumb” that was frequently used in rea-
sonable royalty cases prior to this court’s decision in Uniloc
USA, Inc. v. Microsoft Corp., 632 F.3d 1292, 1315 (Fed. Cir.
2011), which held that “the 25 percent rule of thumb is a
fundamentally flawed tool,” and that the Vonage verdict
was therefore tainted.
    We have already addressed and rejected Time
Warner’s arguments regarding the impropriety of admit-
ting evidence of the Vonage verdict. As for Time Warner’s
argument that the Vonage verdict was tainted by the testi-
mony in that case regarding the 25 percent rule, Sprint’s
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,        9
INC.


expert made clear that he was not relying on that rule in
this case, and the jury in the Vonage case did not return a
verdict that was based on the 25 percent rule as the meas-
ure of damages.
     Both parties’ experts explained that the 25 percent rule
of thumb had been rejected by economists and courts. And
Time Warner cross-examined Sprint’s damages expert at
length about the 25 percent rule in an effort to demonstrate
that the Vonage verdict was tainted by the 25 percent rule
and was therefore unreliable. In effect, Time Warner is
now arguing that the references to the 25 percent rule in
the Vonage case made the verdict in that case per se inad-
missible. We disagree. Time Warner had ample oppor-
tunity at trial to challenge the reliability of the Vonage
verdict on that ground. We conclude that Time Warner has
failed to show that the references to the 25 percent rule in
the Vonage case had such a demonstrable and substantial
effect on that case’s verdict as to disqualify the Vonage ev-
idence from consideration by the jury in determining an ap-
propriate damages award in this case.
    Time Warner next argues that the Vonage verdict
should not have been admitted because the jury in that
case awarded a royalty based on all of Vonage’s VoIP reve-
nues, without determining which portions of the revenues
were attributed to patented technology as opposed to un-
patented features. But the fact that the jury in the Vonage
case awarded a royalty based on total VoIP revenues does
not make that verdict inadmissible; the jury in that case
was called on to make a determination as to the appropri-
ate royalty for the patented technology—the same technol-
ogy at issue in this case—and it did so in the form of a lump
sum royalty award. The reasonable royalty award in the
Vonage case was based on the jury’s determination of the
value of the technology that was taken as a result of
Vonage’s infringement. By operation of the hypothetical
negotiation method of calculating damages, the award com-
pensated Sprint for the incremental value of Sprint’s
10 SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,
                                                  INC.


technology, not for the value of unpatented features of
Vonage’s VoIP system.
     The evidence showed that the damages award in the
Vonage case of $1.37 per subscriber per month was approx-
imately five percent of Vonage’s total VoIP revenues for the
infringement period. The jury settled on the same amount
for the damages award in this case as in the Vonage case.
The Vonage verdict did not stand alone, however. In addi-
tion to the Vonage verdict, the jury had before it two li-
censes from Sprint to other communications companies for
the patented technology, both of which were for approxi-
mately five percent of the companies’ VoIP revenue. The
evidence showed that those licenses, like the Vonage ver-
dict, were based on the value of the patented technology
and not the value of other aspects of the companies’ VoIP
technology that were not covered by Sprint’s patents. 3
    Time Warner argues that Sprint’s damages case was
flawed because Sprint did not apportion the damages
award to the incremental value that the patented invention
added to the end product. See Ericsson, Inc. v. D-Link Sys.,
Inc., 773 F.3d 1201, 1226 (Fed. Cir. 2014). That argument,
however, ignores that the objective of apportionment can
be achieved in different ways, one of which is through the
jury’s determination of an appropriate royalty by applying
the so-called Georgia-Pacific factors, under proper


   3     Time Warner contends that each of the other two
licenses “covers more than the patents Sprint asserts here,”
Reply Br. 20, but the testimony from Sprint’s expert indi-
cates that those two licenses were for the “same technol-
ogy” for the “same patents-in-suit” as in the present case.
As in the case of the Vonage verdict, while those agree-
ments covered numerous patents, Time Warner has not
shown that the additional patents included technology ma-
terially different from the technology covered by the pa-
tents-in-suit in this case.
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,      11
INC.


instructions embodying apportionment principles. See
Exmark Mfg. Co. v. Briggs & Stratton Power Grp., LLC,
879 F.3d 1332, 1349 (Fed. Cir. 2018) (“[T]he standard Geor-
gia-Pacific reasonable royalty analysis takes account of the
importance of the inventive contribution in determining
the royalty rate that would have emerged from the hypo-
thetical negotiation.” (quoting AstraZeneca AB v. Apotex
Corp., 782 F.3d 1324, 1338 (Fed. Cir. 2015))); Ericsson, 773
F.3d at 1228 n.5 (“While factors 9 and 13 of the Georgia-
Pacific factors allude to apportionment concepts, we be-
lieve a separate instruction culled from Garretson [v.
Clark, 111 U.S. 120 (1884)] would be preferable in future
cases.”).
     Such an analysis often considers rates from compara-
ble licenses, and we have explained that “otherwise compa-
rable licenses are not inadmissible solely because they
express the royalty rate as a percentage of total revenues,
rather than in terms of the smallest salable unit.” Com-
monwealth Sci. & Indus. Research Org. v. Cisco Sys., Inc.,
809 F.3d 1295, 1303 (Fed. Cir. 2015). The fact that two
other licenses were granted for the same technology, to-
gether with the Vonage verdict—all of which were for the
same royalty rate as the rate utilized in the Vonage case to
yield the $1.37 per VoIP subscriber per month damages as-
sessment—provides strong support for Sprint’s argument
that the damages award in this case reflected the incre-
mental value of the inventions and thus satisfied the re-
quirement of apportionment. See Ericsson, 773 F.3d at
1227–28 (damages testimony regarding real-world rele-
vant licenses “takes into account the very types of appor-
tionment principles contemplated in Garretson.”).
    Contrary to Time Warner’s contention, the jury’s dam-
ages award was based on the value of what was taken from
Sprint, not the value of unpatented features of Time
Warner’s VoIP system. Sprint’s damages expert addressed
apportionment at some length during his testimony, ex-
plaining that his damages calculations were designed to
12 SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,
                                                  INC.


determine “the incremental profits that are attributable to
the patents in suit.” And the jury was specifically in-
structed on apportionment. The court directed that the
reasonable royalty “must be based on the incremental
value that the patented invention adds to the end product.
When the infringing products have both patented and un-
patented features, measuring this value requires a deter-
mination of the value added by the patented features.”
Time Warner did not propose alternative instructions on
damages, so the issue is simply whether the evidence was
sufficient to support the jury’s award. In light of the
Vonage verdict and the other two licenses, as well as testi-
mony from Sprint’s expert as to the cost to Sprint and the
benefit to Time Warner from Time Warner’s decision to op-
erate the VoIP system itself rather than contracting that
work out to Sprint, the jury had an adequate basis from
which to find that damages should be awarded in the
amount of $1.37 per VoIP subscriber per month.
    Finally, Sprint introduced evidence from which the
jury could conclude that Time Warner did not have availa-
ble to it any reasonable non-infringing alternatives to
Sprint’s patented technology for connecting PSTN net-
works to IP networks. That factor also bears on the amount
of the royalty that a jury could find would emerge from a
hypothetical negotiation, as the absence of non-infringing
alternatives would strengthen the patentee’s hand in such
a negotiation. See Carnegie Mellon Univ. v. Marvell Tech.
Grp., Ltd., 807 F.3d 1283, 1304 (Fed. Cir. 2005) (The hypo-
thetical negotiation seeks to determine “what it would have
been worth to the defendant, as it saw things at the time,
to obtain the authority to use the patented technology, con-
sidering the benefits it would expect to receive from using
the technology and the alternatives it might have pur-
sued.”). In light of all the evidence bearing on the damages
award, we conclude that the jury’s verdict was supported
by sufficient evidence and did not contravene the principles
of apportionment set forth by this court.
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,        13
INC.


       C. THE WRITTEN DESCRIPTION REQUIREMENT
    Time Warner next argues that both the call control pa-
tents and the broadband patents were shown to be invalid
for failure to satisfy the written description requirement
set forth in 35 U.S.C. § 112, ¶ 1 (now 35 U.S.C. § 112(1)).
In particular, Time Warner contends that the specifica-
tions of each group of patents describe the invention as a
method of transmitting signals between a PSTN network
and a packet-switched system that employed Asynchro-
nous Transfer Mode (“ATM”) technology, which used vir-
tual circuits. The specifications, Time Warner argues, do
not describe the invention as including the transmission of
signals from a PSTN network to a packet-switched network
using IP technology. According to Time Warner, the refer-
ences to “broadband” and “packet” in the specifications dis-
close only ATM systems and not IP systems.
    Compliance with the written description requirement
presents a question of fact. Ariad Pharms., Inc. v. Eli Lily
& Co., 598 F.3d 1336, 1355 (Fed. Cir. 2010) (en banc). The
written description issue was submitted to the jury on in-
structions that are not objected to on appeal. Through its
verdict, the jury found that the written description require-
ment was satisfied with respect to both the call control pa-
tents and the broadband patents. As to both sets of
patents, the issue is therefore whether the evidence at trial
was sufficient to satisfy the written description require-
ment. Because the common specifications for each of the
two sets of patents differ significantly, we treat the two in-
validity arguments separately.
              1. THE CALL CONTROL PATENTS
    Time Warner acknowledges that the claims of the call
control patents cover both ATM and IP communication
technology. However, Time Warner contends that the com-
mon specification of the call control patents is confined to
ATM technology, and that the claims of the call control pa-
tents are invalid because, as applied to IP technology, they
14 SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,
                                                  INC.


are not supported by the specification. Sprint responds
that the specification is not confined to ATM technology,
but is broad enough to cover IP technology as well.
     IP technology is not expressly excluded from the call
control specification. Instead, the specification refers to
“[b]roadband systems, such as Asynchronous Transfer
Mode (ATM),” ’561 patent, col. 2, ll. 28-30, a formulation
that strongly suggests that the patents are not limited to
ATM technology. The specification adds that the network
on which the invention operates “could be any type of tele-
communications network that operates using network ele-
ments, signaling, and connections.” Id., col. 8, ll. 38-43.
Importantly, the call control patents disclose means for
routing communications between a point on a narrowband
network, such as the PSTN, and a point on a broadband
network, without specifying whether the point on the
broadband network is part of a fixed end-to-end path for a
single call (as in an ATM-based system) or part of a path
that is established on a packet-by-packet basis by each sep-
arate router (as in an IP-based system). See ’561 patent,
col. 3, ll. 10-20; id., col. 9, line 62, through col. 10, line 39.
     Sprint’s technical expert, Dr. Stephen Wicker, testified
that a person of skill in the art at the time of the application
would have understood the use of the term “broadband” to
include IP as well as ATM technology. He testified that
such a person, reading the common specification of the call
control patents, would conclude that the inventor “was
clearly thinking about broadband technologies that used
routing to individual elements like IP addresses or used
connections as in ATM.” Dr. Wicker pointed out, for exam-
ple, that the call control patents state that the communica-
tion control processor in the system “processes the
signaling and selects at least one network characteristic in
response to the signaling. Network characteristics might
be network elements, connections, network codes, applica-
tions, or control instructions to name a few examples.” ’561
patent, col. 6, ll. 12-16.
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,            15
INC.


    Dr. Wicker explained that the reference to “connec-
tions” was a reference to ATM technology, while the refer-
ence to “network elements” would encompass IP
technology. Those references, according to Dr. Wicker,
showed that the call control patents were directed to “some-
thing more general in the world of broadband networks
than just ATM.”
    Dr. Wicker focused on the passage from the call control
patents’ specification that notes that in one embodiment
the “selection of a network characteristic will include the
selection of a network code,” and that “network codes are
the logical addresses of network elements.” Id., col. 12, ll.
47-56. That passage, he testified, indicates that the speci-
fication contemplated the use of IP technology in addition
to ATM technology, since IP addresses are the logical ad-
dresses of network elements.
     Dr. Wicker also pointed to a passage in the call control
specification providing that the call control processor may
select only network elements and not the connections, and
that the elements would select the connections to use. Id.,
col. 6, line 62, through col. 7, line 9; see also id., col. 7, ll.
22-24 (“The [call control processor] might select all the net-
work elements, a portion of the network elements, or none
of the network elements leaving the switches to select the
remainder.”); id., col. 15, ll. 32-34. Based on the specifica-
tion, Dr. Wicker inferred that the inventor was referring to
“broadband technologies that used routing to individual el-
ements like IP addresses or used connections as in ATM.
He’s looking at both.” In light of the evidence before the
jury on the issue, we cannot conclude that Time Warner
has shown by clear and convincing evidence that the call
control specification lacks an adequate written description
to support the asserted claims.
                2. THE BROADBAND PATENTS
    The common specification of the broadband patents in-
corporates the specification of the call control patents by
16 SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,
                                                  INC.


reference. For the reasons explained with respect to the
call control patents, the written description in the broad-
band patents therefore includes IP technology as well as
ATM technology. That is so even though the broadband
specification itself is principally focused on the operation of
the invention within ATM communication systems.
     In addition to noting that the broadband patents incor-
porate the specification of the call control patents, Dr.
Wicker pointed to particular portions of the broadband
specification to support his opinion that the broadband
specification was not limited to ATM technology with re-
gard to its discussion of the “identifier,” “routing,” and
“asynchronous communication” elements. As for the iden-
tifier, Dr. Wicker testified that a person of ordinary skill
reading the broadband specification would have concluded
that the identifier “could be like an IP address pointing to
a destination, it could be like a VPI/VCI pair pointing to a
virtual connection. [It is] more general than just saying
ATM.” The identifier, he concluded, “could cover any
broadband identifier,” including an IP address. As for
“routing,” Dr. Wicker testified that routing refers to mov-
ing packets toward their destination, with “no limitation on
how that’s done. . . . [T]he route or routing could be any
broadband routing including IP.” As for asynchronous
communication, Dr. Wicker testified that a person of skill
in the art would understand that term, as used in the
broadband specification, “to be more general than just a
particular technology. They would understand it in the
context of the patents to be a broadband packet switching
technology but nothing more specific.” In summary, Dr.
Wicker concluded that the broadband specification was not
limited to a “fixed path” communication system, such as
ATM.
    We are not persuaded by Time Warner’s argument that
the district court’s construction of the phrase “interworking
unit” renders the broadband patent claims invalid. The
district court construed “interworking unit,” which appears
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,       17
INC.


in all asserted claims of the broadband patents, to mean an
“ATM interworking multiplexer.” Time Warner argues
that because other claim elements, discussed in the para-
graph above, are broad enough to encompass technologies
other than ATM that are “incongruous with the claimed
ATM interworking multiplexer,” the claims lack written
description support. However, Sprint’s expert testified,
with a reference to technical literature, that ATM and IP
are actually interoperable such that IP datagrams can be
transmitted over ATM. Time Warner’s expert agreed that
it was technically possible to run IP over an ATM network.
Based on this testimony, a reasonable jury could reject
Time Warner’s argument that it would be “nonsensical” to
use IP with an “ATM interworking multiplexer.”
     Although the broadband patents focus on ATM technol-
ogy, we cannot agree, in light of the record at trial, that
Time Warner has met its burden of showing by clear and
convincing evidence that the common specification of the
broadband patents lacks an adequate written description
of claimed subject matter in those patents.
        D. INFRINGEMENT OF THE BROADBAND PATENTS
            UNDER THE DOCTRINE OF EQUIVALENTS
    Time Warner’s final argument is that the evidence was
insufficient to support the jury’s verdict that the broadband
patents were infringed under the doctrine of equivalents.
The district court construed the term “interworking unit”
in the broadband patents to mean an “ATM interworking
multiplexer.” 4 Presumably for that reason, the jury found
that none of the claims of the broadband patents were di-
rectly infringed. However, the jury found that those pa-
tents were infringed under the doctrine of equivalents.



    4    On appeal, Time Warner does not challenge the
trial court’s construction of the broadband patent claims or
the court’s instructions on the doctrine of equivalents.
18 SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,
                                                  INC.


    At trial, Sprint introduced evidence that Time
Warner’s MGX8880 media gateway, which uses an IP card
to convert data to IP packets, was interchangeable with an
ATM interworking multiplexer, and therefore satisfied the
“interworking unit” limitation under the doctrine of equiv-
alents. See Warner-Jenkinson Co. v. Hilton Davis Chem.
Co., 520 U.S. 17, 36 (1997) (“The known interchangeability
of substitutes for an element of a patent is one of the ex-
press objective factors . . . bearing upon whether the ac-
cused device is substantially the same as the patented
invention.”).
    The evidence of interchangeability was sufficient to
sustain the jury’s verdict. Dr. Wicker testified that the
MGX8880 was designed with interchangeable cards that
allowed the medial gateway to handle either ATM or IP
packets. The fact that swapping cards was possible and
was contemplated by skilled artisans supports the jury’s
conclusion that the IP-based system was equivalent to the
ATM-based system for purposes of the doctrine of equiva-
lents. See Interactive Pictures Corp. v. Infinite Pictures,
Inc., 274 F.3d 1371, 1383–84 (Fed. Cir. 2001).
     To be sure, the evidence showed that converting Time
Warner’s established network from IP to ATM technology
would have entailed substantial work and expense. How-
ever, the fact that the choice of one of two technologies
would be expensive to reverse, once the choice was made
and resources were invested in that choice, does not mean
that the two competing choices were not equivalent in the
first instance. Sprint introduced evidence that at the out-
set the choice between ATM and IP technology, as related
to the invention set forth in the broadband patents, was
simply a design choice. That evidence supports the jury’s
verdict of equivalency.
    In addition, Dr. Wicker testified at length regarding
how Time Warner’s IP system satisfied the function-way-
result test for equivalency for each of the asserted
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,      19
INC.


broadband claims. See Sofamor Danek Grp., Inc. v. DePuy-
Motech, Inc., 74 F.3d 1216, 1221–22 (Fed. Cir. 1996). He
explained that the MGX8880 performed the same function
as the interworking unit recited in the claims, that it did
so in the same way as the claimed unit, and that it achieved
the same result.
   Based on the evidence of equivalency adduced at trial,
we hold that Time Warner has failed to show that the evi-
dence was insufficient to support the jury’s verdict.
                       AFFIRMED
       NOTE: This disposition is nonprecedential.


  United States Court of Appeals
      for the Federal Circuit
                 ______________________

   SPRINT COMMUNICATIONS COMPANY, L.P.,
              Plaintiff-Appellee

                            v.

  TIME WARNER CABLE, INC., TIME WARNER
 CABLE, LLC, TIME WARNER ENTERTAINMENT
        COMPANY, L.P., TIME WARNER
   ENTERTAINMENT-ADVANCE/NEWHOUSE
 PARTNERSHIP, TWC COMMUNICATIONS, LLC,
TIME WARNER CABLE INFORMATION SERVICES
                (KANSAS), LLC,
              Defendants-Appellants
             ______________________

                       2017-2247
                 ______________________

MAYER, Circuit Judge, dissenting.
    This case involves a remarkable mismatch between
the narrow patent disclosures and the exceedingly broad
claims. The patents asserted by Sprint Communications
Company, L.P. (“Sprint”) are invalid as a matter of law
because their specifications provide no written description
support for the full breadth of the asserted claims. I
therefore respectfully dissent.
   The specifications of Sprint’s patents describe ways to
address the problems that arise when trying to connect
2   SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,
                                                   INC.


Asynchronous Transfer Mode (“ATM”) systems with the
traditional Public Switched Telephone Network (“PSTN”).
J.A. 185–88; see also J.A. 5166–69. The specifications do
not mention Internet Protocol (“IP”) communications or
contain any suggestion that methods of establishing
interconnections between IP networks and the PSTN are
within the scope of the claimed invention.
    The common specification of Sprint’s Call Control Pa-
tents, U.S. Patent Nos. 6,463,052 and 6,633,561, describes
a purportedly novel way of linking ATM networks with
the PSTN. It discusses establishing fixed end-to-end
communications paths for calls using PSTN circuits and
ATM virtual circuits. See, e.g., J.A. 185 (2:28–37), 187
(5:16–21), 190 (12:35–46). It further discloses a “Commu-
nication Control Processor,” which interfaces with the
switches to set up a fixed end-to-end path for a call. J.A.
187 (5:30), 190 (11:58–12:4); see also J.A. 177–180.
    Importantly, however, the specification contains no
disclosure of IP technology, which operates in a funda-
mentally different way than ATM technology. Unlike an
ATM network, an IP network does not use circuits or
virtual circuits and does not set up a fixed path for a call.
See J.A. 3872–73, 4414–15. To the contrary, each packet
with data for a call is routed using an identifier in the
packet known as an “IP address.” See J.A. 3872–73. As
an expert for Time Warner Cable, Inc. and related parties
explained, ATM is “like being on a train track where you
have to follow the tracks,” but IP is like “driving a car
from Point A to [Point] B, where you’re free to take differ-
ent roads.” J.A. 4827–28; see also J.A. 4413–15. The
common specification of the Call Control Patents does not
contain any disclosure of IP technology, which is unsur-
prising given that it is directed to setting up fixed end-to-
end communications paths and IP routing does not rely on
such paths.
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,        3
INC.


     Sprint argues that its “Call Control Patents disclose
inventions for routing communications between a point on
a narrowband network and a point on a broadband net-
work, without regard for whether the point in a broad-
band network is part of a fixed path or is established on a
call-by-call basis.” Br. of Plaintiff-Appellee at 56. In
support, it contends that the common specification of the
Call Control Patents “describe[s] a flexible processing
system that may select ‘all,’ ‘a portion,’ or ‘none’ of the
network elements, as well as ‘all,’ ‘a portion,’ or ‘none’ of
the connections, in performing the steps of the claims.”
Id. (quoting J.A. 188 (7:22–29)). In essence, Sprint argues
that the specification does not require the selection of all
of the network elements and connections in a communica-
tions path. This argument fails. The common specifica-
tion makes clear that the Communication Control
Processor and the switches will function together to select
all of the network elements and connections. See J.A. 188
(7:20–29) (“One skilled in the art will recognize that the
selection process can be distributed among the [Commu-
nication Control Processor] and the elements. The [Com-
munication Control Processor] might select all the
network elements, a portion of the network elements, or
none of the network elements leaving the switches to select
the remainder.” (emphasis added)). Over and over again,
the specification refers to establishing a communications
path. See, e.g., J.A. 185 (1:37–46), 186 (3:15–18), 190
(11:35–36). It contains nothing even arguably suggesting
that a fixed communications path will not be established,
as would be the case if the claimed invention encom-
passed IP technology.
    Like its Call Control Patents, Sprint’s Broadband Pa-
tents, U.S. Patent Nos. 6,343,084, 6,473,429, and
6,298,064, lack written description support. The purport-
ed invention described in the common specification of the
Broadband Patents is an alternative technique for includ-
ing both PSTN circuits and virtual circuits in the same
4   SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,
                                                   INC.


communications path. See J.A. 303–05. The specifica-
tion’s disclosure makes sense only in the context of ATM
technology. The common specification does not disclose
any packet identifiers other than ATM VPI/VCI identifi-
ers, any routing other than ATM routing, or any form of
asynchronous communication other than ATM. See J.A.
242–53. Importantly, moreover, all of the claims of the
Broadband Patents, as construed by the district court,
require an “ATM interworking multiplexer.” J.A. 352–55.
There is no dispute that an ATM interworking multiplex-
er converts calls between PSTN and ATM formats, allow-
ing the two types of networks to be bridged. J.A. 3689; see
also J.A. 3863, 4485–86, 5280–81. Nothing in the com-
mon specification suggests or even hints that converting
to and from IP or routing over an IP network is within the
scope of the claimed invention.
    Sprint attempts to salvage the verdict of no invalidity
by arguing that the jury was entitled to rely on the testi-
mony of its expert, Dr. Steven Wicker, who stated that the
asserted patents met the written description requirement.
See J.A. 5638–43, 5647–50, 5670–76. This argument is
unpersuasive. Wicker’s statements were conclusory and
unsupported by any persuasive citation to the patent
disclosures or other record evidence. See, e.g., ActiveVideo
Networks, Inc. v. Verizon Commc’ns, Inc., 694 F.3d 1312,
1327 (Fed. Cir. 2012) (declining to credit expert testimony
that “was conclusory and factually unsupported”).
    Wicker argued that IP networks are within the scope
of the claimed invention because there are technologies
that can “force” an IP network to set up and use a fixed
communications path. See J.A. 5738–39, 5651–56. This
argument is premised on a misapprehension of the ade-
quate written description requirement.       The salient
question “is whether the disclosure . . . reasonably con-
veys to those skilled in the art that the inventor had
possession of the claimed subject matter as of the filing
date,” Ariad Pharm., Inc. v. Eli Lilly & Co., 598 F.3d
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER CABLE,      5
INC.


1336, 1351 (Fed. Cir. 2010) (en banc), not whether an
undisclosed technology can be “forced” to operate within
the disclosed system. See Lockwood v. Am. Airlines, Inc.,
107 F.3d 1565, 1572 (Fed. Cir. 1997) (“It is not sufficient
for purposes of the written description requirement of
§ 112 that the disclosure, when combined with the
knowledge in the art, would lead one to speculate as to
[the] modifications that the inventor might have envi-
sioned, but failed to disclose.”).
     “[T]he purpose of the written description requirement
is to ensure that the scope of the right to exclude, as set
forth in the claims, does not overreach the scope of the
inventor’s contribution to the field of art as described in
the patent specification.” Ariad, 598 F.3d at 1353–54
(citations and internal quotation marks omitted). Sprint
overreaches here. It seeks broad monopoly rights over
interconnections between narrowband and broadband
networks. Nothing in the patent specifications, however,
is sufficient to sweep non-path technologies like IP within
the scope of the claimed invention. See Gentry Gallery,
Inc. v. Berkline Corp., 134 F.3d 1473, 1480 (Fed. Cir.
1998) (explaining that “claims may be no broader than the
supporting disclosure”). I would reverse.
