       NOTE: This disposition is nonprecedential.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.
                 ______________________

              Decided: November 30, 2018
                ______________________

    J. MICHAEL JAKES, Finnegan, Henderson, Farabow,
Garrett & Dunner, LLP, Washington, DC, argued for
plaintiff-appellee. Also represented by KATHLEEN DALEY,
JASON LEE ROMRELL; ROB RECKERS, Shook, Hardy &
2          SPRINT COMMUNICATIONS COMPANY v. TIME WARNER
                                              CABLE, INC.


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 &
Porter 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.
Amicus 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 (collective-
ly, “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
patent”); 6,343,084 (“the ’084 patent”); 6,463,052 (“the
’052 patent”); 6,473,429 (“the ’429 patent”); and 6,633,561
(“the ’561 patent”). Following trial, the jury found all five
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER              3
CABLE, INC.


patents 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
telephone communications known as the Public Switched
Telephone 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
network, 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 between the switches establishes a fixed circuit
for the entire call, and the call occupies the entire band-
width of that circuit 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.
Accordingly, communications companies developed pack-
et-based solutions to increase the efficiency of data com-
munications. Two types of packet-based technology that
are pertinent to this case emerged: (1) asynchronous
transfer mode technology (“ATM”), which used “virtual
circuits” that established fixed routes for communications
4          SPRINT COMMUNICATIONS COMPANY v. TIME WARNER
                                              CABLE, INC.


but enabled 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 routing decision for each packet based on the
ultimate destination of the packet. In the IP system,
individual packets that are part of a single communica-
tion 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
Protocol (“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
evidence 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 tech-
nology 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
damages under a hypothetical negotiation theory. The
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER             5
CABLE, INC.


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 invaria-
bly improper, that is not the rule that this court has
applied. Instead, the court has held that such evidence
can be admissible 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
between 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 appellant 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 prejudi-




   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
6          SPRINT COMMUNICATIONS COMPANY v. TIME WARNER
                                              CABLE, INC.


cial 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 limited 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
reasonable 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



Motor Co. v. Chrysler Corp., 525 F.2d 1338, 1351 (3d Cir.
1975), a case on which Time Warner heavily relies.
    2   While Time Warner cites several cases that have
disapproved of the admission of evidence regarding the
outcome of earlier cases, none of those cases is persuasive
authority 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
district court did not abuse its discretion by excluding
evidence 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 instruc-
tion. 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 war-
rants.” 525 F.2d at 1351.
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER             7
CABLE, INC.


in 2010, and a reasonable jury could well conclude that
the verdict and the amount of damages awarded in a
similar prior litigation would have influenced the outcome
of a hypothetical negotiation in the case at bar.
    Importantly, the district court gave the jury limiting
instructions that the Vonage evidence was to be consid-
ered 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 rele-
vance grounds. We disagree. While there are some
differences between the two proceedings, the core allega-
tions 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 technol-
ogy asserted in the Vonage case was materially different
from the technology raised in this case. Any differences
between the two proceedings, moreover, were available to
Time Warner to argue 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 refer-
ences to the jury verdict about which Time Warner com-
plains were made in the context of a discussion of the
hypothetical negotiation. Several of the references were
made in Sprint’s opening statement. No objection was
raised to those remarks as exceeding the limited grounds
on which the district court permitted the Vonage evidence
8          SPRINT COMMUNICATIONS COMPANY v. TIME WARNER
                                              CABLE, INC.


to be used. In closing argument, Sprint’s counsel again
referred to the Vonage verdict as it bore on the hypothet-
ical negotiation issue and on the issue of willfulness, as
the district court had permitted. Having examined each
of counsel’s references to the prior verdict, as well as the
evidence regarding the Vonage verdict that was intro-
duced at trial, we are satisfied 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 evidence 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 rea-
sons that Time Warner objected to the admission of
evidence of the Vonage verdict, the damages award
should be overturned because Sprint’s damages expert
relied on that verdict 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
verdict 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 frequent-
ly used in reasonable 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 Warn-
er’s arguments regarding the impropriety of admitting
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER            9
CABLE, INC.


evidence of the Vonage verdict. As for Time Warner’s
argument that the Vonage verdict was tainted by the
testimony in that case regarding the 25 percent rule,
Sprint’s 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 measure 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 inadmissible. We disagree. Time Warner had
ample opportunity 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 demonstra-
ble and substantial effect on that case’s verdict as to
disqualify the Vonage evidence from consideration by the
jury in determining an appropriate 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
revenues, without determining which portions of the
revenues were attributed to patented technology as
opposed to unpatented 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 determina-
tion as to the appropriate royalty for the patented tech-
nology—the same technology 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
10         SPRINT COMMUNICATIONS COMPANY v. TIME WARNER
                                              CABLE, INC.


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 calcu-
lating damages, the award compensated Sprint for the
incremental value of Sprint’s 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 ap-
proximately 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 addition to the Vonage verdict, the jury had
before it two licenses from Sprint to other communica-
tions companies for the patented technology, both of
which were for approximately five percent of the compa-
nies’ VoIP revenue. The evidence showed that those
licenses, like the Vonage verdict, 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 inven-
tion added to the end product. See Ericsson, Inc. v. D-


     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 indicates that those two licenses were for the
“same technology” for the “same patents-in-suit” as in the
present case. As in the case of the Vonage verdict, while
those agreements covered numerous patents, Time Warn-
er has not shown that the additional patents included
technology materially different from the technology
covered by the patents-in-suit in this case.
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER            11
CABLE, INC.


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 determination of an appropriate
royalty by application of the so-called Georgia-Pacific
factors. See Exmark Mfg. Co. v. Briggs & Stratton Power
Grp., LLC, 879 F.3d 1332, 1349 (Fed. Cir. 2018) (“[T]he
standard Georgia-Pacific reasonable royalty analysis
takes account of the importance of the inventive contribu-
tion in determining the royalty rate that would have
emerged from the hypothetical negotiation.”) (quoting
AstraZeneca AB v. Apotex Corp., 782 F.3d 1324, 1338
(Fed. Cir. 2015)). Such an analysis often considers rates
from comparable licenses, and we have explained that
“otherwise comparable licenses are not inadmissible
solely because they express the royalty rate as a percent-
age of total revenues, rather than in terms of the smallest
salable unit.” Commonwealth Sc. & Indus. Research
Organisation v. Cisco Sys., Inc., 809 F.3d 1295, 1303 (Fed.
Cir. 2015). The fact that two other licenses were granted
for the same technology, together with the Vonage ver-
dict—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 assessment—
provides strong support for Sprint’s argument that the
damages award in this case reflected the incremental
value of the inventions and thus satisfied the requirement
of apportionment. See Ericsson, 773 F.3d at 1227–28
(damages testimony regarding real-world relevant licens-
es “takes into account the very types of apportionment
principles contemplated in Garretson [v. Clark, 111 U.S.
120 (1884)]).”
    Contrary to Time Warner’s contention, the evidence
indicates that the jury’s damages award was based on the
value of what was taken from Sprint, not the value of
unpatented features of Time Warner’s VoIP system. Time
Warner did not propose alternative jury instructions on
12         SPRINT COMMUNICATIONS COMPANY v. TIME WARNER
                                              CABLE, INC.


the issue of 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 testimony from Sprint’s expert as to the cost to
Sprint and the benefit to Time Warner from Time Warn-
er’s decision to operate 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 avail-
able 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 hypothetical 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, considering the benefits it would
expect to receive from using the technology and the alter-
natives it might have pursued.”). In light of all the evi-
dence 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.
      C. THE WRITTEN DESCRIPTION REQUIREMENT
    Time Warner next argues that both the call control
patents and the broadband patents were shown to be
invalid for failure to satisfy the written description re-
quirement set forth in 35 U.S.C. § 112, ¶ 1 (now 35 U.S.C.
§ 112(1)). In particular, Time Warner contends that the
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER              13
CABLE, INC.


specifications of each group of patents describe the inven-
tion as a method of transmitting signals between a PSTN
network and a packet-switched system that employed
Asynchronous Transfer Mode (“ATM”) technology, which
used virtual 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 references to “broadband” and “packet” in the
specifications disclose 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 instructions that are not objected to on appeal.
Through its verdict, the jury found that the written
description requirement was satisfied with respect to both
the call control patents 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 requirement. Because the common specifica-
tions for each of the two sets of patents differ significant-
ly, we treat the two invalidity 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
common specification of the call control patents is con-
fined to ATM technology, and that the claims of the call
control patents are invalid because, as applied to IP
technology, they are not supported by the specification.
Sprint responds that the specification is not confined to
ATM technology, but is broad enough to cover IP technol-
ogy as well.
14          SPRINT COMMUNICATIONS COMPANY v. TIME WARNER
                                               CABLE, INC.


    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
telecommunications network that operates using network
elements, 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
separate 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, testi-
fied 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 specifi-
cation of the call control patents, would conclude that the
inventor “was clearly thinking about broadband technolo-
gies that used routing to individual elements like IP
addresses or used connections as in ATM.” Dr. Wicker
pointed out, for example, that the call control patents
state that the communication 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, applications, or control in-
structions to name a few examples.” ’561 patent, col. 6, ll.
12-16.
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER               15
CABLE, INC.


    Dr. Wicker explained that the reference to “connec-
tions” was a reference to ATM technology, while the
reference to “network elements” would encompass IP
technology. Those references, according to Dr. Wicker,
showed that the call control patents were directed to
“something more general in the world of broadband
networks than just ATM.”
    Dr. Wicker focused on the passage from the call con-
trol patents’ specification that notes that in one embodi-
ment the “selection of a network characteristic will
include the selection of a network code,” and that “net-
work codes are the logical addresses of network ele-
ments.” Id., col. 12, ll. 47-56. That passage, he testified,
indicates that the specification contemplated the use of IP
technology in addition to ATM technology, since IP ad-
dresses are the logical addresses of network elements.
     Dr. Wicker also pointed to a passage in the call con-
trol specification providing that the call control processor
may select only network elements and not the connec-
tions, 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 network 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 specification, Dr. Wicker inferred that the
inventor was referring to “broadband technologies that
used routing to individual elements 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.
16         SPRINT COMMUNICATIONS COMPANY v. TIME WARNER
                                              CABLE, INC.


               2. THE BROADBAND PATENTS
    The common specification of the broadband patents
incorporates the specification of the call control patents by
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
incorporate the specification of the call control patents,
Dr. Wicker pointed to particular portions of the broad-
band specification to support his opinion that the broad-
band specification was not limited to ATM technology
with regard to its discussion of the “identifier,” “routing,”
and “asynchronous communication” elements. As for the
identifier, 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
moving packets toward their destination, with “no limita-
tion on how that’s done. . . . [T]he route or routing could
be any broadband routing including IP.” As for asynchro-
nous 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.
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER             17
CABLE, INC.


     We are not persuaded by Time Warner’s argument
that the district court’s construction of the phrase “inter-
working unit” renders the broadband patent claims
invalid. The district court construed “interworking unit,”
which appears 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 paragraph above, are broad enough to
encompass technologies other than ATM that are “incon-
gruous 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 tech-
nology, 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 descrip-
tion 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 “in-
terworking unit” in the broadband patents to mean an
18         SPRINT COMMUNICATIONS COMPANY v. TIME WARNER
                                              CABLE, INC.


“ATM interworking multiplexer.” 4 Presumably for that
reason, the jury found that none of the claims of the
broadband patents were directly infringed. However, the
jury found that those patents were infringed under the
doctrine of equivalents.
    At trial, Sprint introduced evidence that Time Warn-
er’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
equivalents. See Warner-Jenkinson Co. v. Hilton Davis
Chem. Co., 520 U.S. 17, 36 (1997) (“The known inter-
changeability of substitutes for an element of a patent is
one of the express objective factors . . . bearing upon
whether the accused 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.
However, the fact that the choice of one of two technolo-
gies would be expensive to reverse, once the choice was



     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.
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER             19
CABLE, INC.


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 outset the choice between ATM and IP technology, as
related to the invention set forth in the broadband pa-
tents, 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 broad-
band 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 func-
tion 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
evidence 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
                 ______________________

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

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
2          SPRINT COMMUNICATIONS COMPANY v. TIME WARNER
                                              CABLE, INC.


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
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-
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER               3
CABLE, INC.


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 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-
4          SPRINT COMMUNICATIONS COMPANY v. TIME WARNER
                                              CABLE, INC.


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
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-
SPRINT COMMUNICATIONS COMPANY v. TIME WARNER             5
CABLE, INC.


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
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.
