United States Court of Appeals 

for the Federal Circuit ______________________ 

STARHOME GMBH,

Plaintiff-Appellant,

v.

AT&T MOBILITY LLC, ROAMWARE, INC., AND

T-MOBILE USA, INC.,

Defendants-Appellees.

______________________ 

2012-1694

______________________ 

Appeal from the United States District Court for the 

District of Delaware in No. 10-CV-0434, Chief Judge 

Gregory M. Sleet.

______________________ 

Decided: February 24, 2014 

______________________ 

JOHN M. DIMATTEO, Willkie Farr & Gallagher, LLP, 

of New York, New York, argued for plaintiff-appellant. 

With him on the brief was ROBERT G. KOFSKY. Of counsel 

was JESENIA M. RUIZ DE LA TORRE. 

MARK A. PERRY, Gibson Dunn & Crutcher, LLP, of 

Washington, DC, argued for defendants-appellees. On the 

brief were JOSH KREVITT, BENJAMIN HERSHKOWITZ, and R.

SCOTT ROE, of New York, New York; and FREDERICK 

CHUNG, of Palo Alto, California.

______________________ 
2 STARHOME GMBH v. AT&T MOBILITY LLC

Before MOORE, SCHALL, and REYNA, Circuit Judges.

SCHALL, Circuit Judge.

This is a patent infringement case. Starhome GmbH 

(“Starhome”) sued AT&T Mobility LLC, Roamware, Inc., 

and T-Mobile USA, Inc. (“Defendants”), in the United 

States District Court for the District of Delaware for 

infringement of U.S. Patent No. 6,920,487 (the “’487 

patent”). The ’487 patent is titled “System and Methods 

for Global Access to Services for Mobile Telephone Subscribers.” It relates generally to a way of improving the 

functionality of phone services for users in a roaming

telephone network. To allow users in a roaming network 

to make calls as if in their home network, the ’487 patent 

discloses the use of an “intelligent gateway.” 

Following a Markman hearing, the district court construed various terms of the ’487 patent. Among them was 

the term “intelligent gateway,” which the court construed 

to mean “a network element that transfers information to 

and from a mobile network and another network external

to the mobile network.” Relying upon that construction, 

Defendants moved for summary judgment of noninfringement. Starhome did not contest the motion, but 

instead stipulated to a judgment of noninfringement 

based upon the court’s construction of “intelligent gateway.” Following the district court’s entry of the stipulated 

judgment on September 12, 2012, Starhome GmbH v. 

AT&T Mobility LLC, No. 1:10-cv-00434-GMS (D. Del.

Sept. 12, 2012), Starhome appealed. We affirm.

BACKGROUND

I. STARHOME AND THE ’487 PATENT

Starhome owns the ’487 patent. The problem the patent aims to solve arises when mobile phone users are in a 

network other than their home network (e.g., roaming). 

In a home network, a mobile phone user might dial a 
STARHOME GMBH v. AT&T MOBILITY LLC 3

short code, such as “121,” to access voice mail. But while 

roaming, the visiting network may not recognize the code, 

resulting in an error message. As another example, a 

user from Germany visiting the United States may want 

to call home to Germany, but if the user does not enter 

the correct international direct-dialing prefix and country 

code, the call will not connect. 

The ’487 patent’s solution to this problem is the “intelligent gateway.” Figure 1 of the ’487 patent, shown below,

demonstrates a system (10) providing roaming services 

and employing the intelligent gateway. 

As shown in Figure 1, the intelligent gateway (V-I/G 

32) has a database (DB 31) that contains information 

about multiple home networks, including short-code 

translation tables, subscriber profile data, and roaming 

patterns. ’487 patent col. 2 ll. 33–41. The information in 

the database may be updated via a global packet-switch 

network (22). Id. col. 2 ll. 33–36, col. 4 ll. 33–36. Figure 2 

of the ’487 patent, shown below, demonstrates a call flow 
4 STARHOME GMBH v. AT&T MOBILITY LLC

of a short-coded call or erroneous full-number call in 

accordance with the system of Figure 1. Id. col. 1 ll. 43–

44, col. 3 ll. 24–27. The specification explains that, “[i]n 

order to simplify the picture, the mobility probe and its 

Interfaces are not shown.” Id. col. 3 ll. 27–29. 

In Figure 2, the visited mobile network (VPLMN 30) 

has a switching center (V-MSC 34) supporting a roaming 

cell phone (39). If the roaming subscriber (39) dials a 

phone number that the switching center (34) cannot place 

(e.g., a voice mail short code like “121”) (step 1), the call is 

routed to the intelligent gateway (V-I/G 32) (step 2). The 

intelligent gateway, which has knowledge of the homenetwork dialing format and short codes, translates the 

sequence into one the switch (34) will recognize and sends 

the corrected dialing sequence back to the switch (step 3). 

The call is then routed by the switch to the international 

telephone network (step 4), and the network sends the 

call to its intended destination (step 5). Id. col. 3 l. 30 – 

col. 4 l. 5. 
STARHOME GMBH v. AT&T MOBILITY LLC 5

Starhome sells its intelligent gateway solution as the 

IntelliGateTM and has installed it in over 130 mobile 

networks throughout the world. 

II. DEFENDANTS AND THE ACCUSED PRODUCT

Defendant Roamware sells a network platform that 

runs Smart Call Assistant and Short Code applications. 

Those applications allow mobile-network operators to 

translate numbers dialed by roaming cell-phone users 

visiting their networks. Defendants AT&T and T-Mobile 

use the Roamware platforms in their networks. Notably, 

the Roamware platform does not connect to an external 

packet-switch network or other external network. 

III. THE DISTRICT COURT PROCEEDINGS 

Starhome filed its complaint against Defendants on 

May 25, 2010, asserting infringement of the ’487 patent

and U.S. Patent No. 7,231,431 (the “’431 patent”), which 

is a continuation of the ’487 patent. The parties disputed 

multiple terms in the patents, one being the term “intelligent gateway.” Starhome proposed that the term meant 

“a network element that uses knowledge implemented in 

databases or the like and application logic to perform its 

operations.” Defendants argued that the term meant “a 

network element that transfers information to and from a 

mobile network and another network external to the 

mobile network.” 

After briefing and a Markman hearing, the district 

court issued its claim construction order. In that order, 

the court found that the word “gateway” had a wellknown technical meaning in the telecommunications 

industry when the application for the asserted patents 

was filed. In support of its finding, the court relied on the 

Institute of Electrical and Electronics Engineers (“IEEE”)

dictionary, which describes a “gateway” as a device that 

connects two or more networks. Concluding that the 
6 STARHOME GMBH v. AT&T MOBILITY LLC

inventors did not clearly redefine the term, the court 

accepted Defendants’ proposed construction.

Based on the claim construction order, the parties 

filed letter briefs requesting permission to move for summary judgment. Finding that Defendants set forth a 

compelling argument for non-infringement based on the 

construction of “intelligent gateway,” the court granted 

Defendants’ request. Rather than formally brief the 

issue, Starhome stipulated to the entry of judgment of 

noninfringement. 

Starhome timely appealed as to the ’487 patent. 

Starhome no longer asserts the ’431 patent. We have 

jurisdiction pursuant to 28 U.S.C. § 1295(a)(1). 

DISCUSSION

I. STANDARD OF REVIEW

Where, as here, a plaintiff concedes noninfringement 

by stipulation, we need only address the district court’s 

construction of the pertinent claims. Altiris, Inc. v. Symantec Corp., 318 F.3d 1363, 1368 (Fed. Cir. 2003). 

Claim construction is a question of law that we review de 

novo. Cybor Corp. v. FAS Techs., Inc., 138 F.3d 1448, 

1451 (Fed. Cir. 1998) (en banc). 

II. THE PARTIES’ CONTENTIONS

Starhome asserts independent claims 10 and 40 of the 

’487 patent. Claim 10 recites the following:

10. A system comprising:

an intelligent gateway associated with a first

mobile telephone network,

said first mobile telephone network having

connections to other mobile telephone networks,

said intelligent gateway adapted to translate a

dialing sequence when dialed by a roaming cellu-
STARHOME GMBH v. AT&T MOBILITY LLC 7

lar telephony device roaming in said first mobile 

network into a destination number,

said roaming cellular telephony device having 

a home network which is other than said first mobile network; 

and a routing center in said first mobile telephone network, 

said routing center adapted to route said dialing sequence within said first mobile telephone 

network to said intelligent gateway for said translating.

Claim 40 recites the following:

40. An intelligent gateway associated with a 

first cellular telephony network,

adapted to provide assistance to a cellular telephony device roaming in said first cellular telephony network to complete calls when a 

destination number dialed by said roaming cellular telephony device is erroneous, 

said roaming cellular telephony device being

registered as a home device in a second cellular

telephony network being distinct from said first 

cellular telephony network, and 

said intelligent gateway being adapted to obtain information for said call completion using 

knowledge of said second cellular telephony network.

On appeal, Starhome asserts the same construction of 

“intelligent gateway” that it urged in the district court (“a 

network element that uses knowledge implemented in 

databases or the like and application logic to perform its 

operations”). In support of that construction, Starhome 

argues that the specification does not require the gateway 
8 STARHOME GMBH v. AT&T MOBILITY LLC

to be connected to an external network. Rather, Starhome contends, the specification explains that the intelligent gateway has a local database of information it 

accesses to perform its functions. Some embodiments 

employ a single intelligent gateway associated with a 

single mobile network, Starhome argues, while others 

disclose multiple intelligent gateways associated with an 

external packet-switch network. The critical part of the 

specification, Starhome continues, is Figure 2, which 

shows the intelligent gateway connected solely to the 

internal network. Construing “intelligent gateway” to 

require the transfer of information to and from an external network, Starhome concludes, expressly excludes the 

embodiment of Figure 2. 

Further, Starhome argues, claim differentiation supports its proposed construction. According to Starhome, 

claims 10 and 40 do not expressly or impliedly require the 

intelligent gateway to transfer information to and from an 

external network. By contrast, unasserted claims 1 and 

47 recite a connection to an external packet-switch network. This substantive difference between the claims, 

Starhome concludes, demonstrates that a connection to an 

external network is not a required feature of an intelligent gateway. 

Defendants argue that the patentee used the specific 

term “gateway” rather than a generic network element, 

and that the common usage of that term should control. 

Defendants thus argue that the district court correctly 

construed “intelligent gateway” as “a network element 

that transfers information to and from a mobile network 

and another network external to the mobile network.” In 

support of that construction, Defendants point to three 

dictionaries showing that “gateway” refers to a point of 

interconnection between networks at which information 

transfer occurs. 
STARHOME GMBH v. AT&T MOBILITY LLC 9

Further, Defendants argue, the specification describes 

the “present invention” as intelligent gateways connecting 

different networks. Likewise, Defendants continue, the 

’487 patent incorporates by reference a Patent Cooperation Treaty (“PCT”) application, which describes the 

“present invention” as a system that “transfer[s] certain 

signals over a packet-switch network through service 

nodes connected to the telephone networks.” Joint Appendix (“J.A.”) 4803. The service nodes are intelligent 

gateways, Defendants contend, and are associated with a 

first mobile network directly connected to an external 

network. 

Moreover, Defendants argue, every embodiment in 

the ’487 patent requires the intelligent gateway to directly connect different networks. In the first embodiment 

(Figures 1 and 2), the visited mobile network may be 

coupled to a global packet-switch network via a visited 

intelligent gateway. In the second embodiment (Figures 

3–5), in addition to the visited intelligent gateway, a 

home network is coupled to a global packet-switch network via a home intelligent gateway. Notably, Defendants argue, the specification describes no system where 

the intelligent gateway is not connecting two different 

networks. 

Regarding Starhome’s argument that Figure 2 is a 

separate embodiment, Defendants respond that the figure 

merely illustrates a call flow occurring within the larger 

system of Figure 1. The figure omits components not 

essential to explaining the call flow, Defendants continue, 

and is not a separate embodiment. 

Turning to Starhome’s argument based upon claim 

differentiation, Defendants respond that the doctrine does 

not apply because each dependent claim in the ’487 patent 

adds a feature not otherwise required by the independent 

claims. Specifically, Defendants argue, the district court’s 

construction requires access to a generic external net-
10 STARHOME GMBH v. AT&T MOBILITY LLC

work, but the dependent claims recite access to a specific 

type of network.

In further support of their position, Defendants point 

to statements that Starhome made in a related foreign 

application. To overcome prior art during prosecution of a 

European application that claims priority to the same 

provisional application as the ’487 patent, Starhome 

argued that “a gateway provides access to an external 

environment beyond the immediate network,” and is 

defined “in terms of an access means from one network to 

another.” Those statements, Defendants urge, should 

preclude Starhome from now advocating a broader construction.

In response, Starhome argues that its statements in 

connection with the PCT application are consistent with 

its proposed construction. The prior art at issue in the 

European application did not involve roaming, Starhome 

continues, so when the prosecuting attorney said the 

gateway accessed an external network, he was referring 

to another telephone network. Accessing a separate 

telephone network, Starhome concludes, is exactly what 

the intelligent gateway accomplishes. 

III. ANALYSIS

“The words of a claim are generally given their ordinary and customary meaning as understood by a person 

of ordinary skill in the art when read in the context of the 

specification and prosecution history.” Thorner v. Sony 

Computer Entm’t Am. LLC, 669 F.3d 1362, 1365 (Fed. Cir. 

2012) (citing Phillips v. AWH Corp., 415 F.3d 1303, 1313 

(Fed. Cir. 2005) (en banc)). “There are only two exceptions to this general rule: 1) when a patentee sets out a 

definition and acts as his own lexicographer, or 2) when 

the patentee disavows the full scope of a claim term either 

in the specification or during prosecution.” Id. (citing 

Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1580 

(Fed. Cir. 1996)). 
STARHOME GMBH v. AT&T MOBILITY LLC 11

We have made clear that dictionaries and treatises 

can often be useful in claim construction, particularly 

insofar as they help the court “‘to better understand the 

underlying technology’ and the way in which one of skill 

in the art might use the claim terms.” Phillips, 415 F.3d 

at 1318 (quoting Vitronics Corp., 90 F.3d at 1584 n.6). 

Moreover, judges are free to rely on dictionaries at any 

time during the process of construing claims “so long as 

the dictionary definition does not contradict any definition 

found in or ascertained by a reading of the patent documents.” Id. at 1322–23 (quoting Vitronics Corp., 90 F.3d 

at 1584 n.6).

Both asserted claims recite an “intelligent gateway.” 

The term “gateway” had a well-understood meaning in 

the art at the time the patentees filed the application that 

led to the ’487 patent. As evidenced by technical dictionaries, one of ordinary skill in the art would have understood a “gateway” to be a connection between different 

networks. See Andrew S. Tanenbaum, Computer Networks 16 (3d ed. 1996) (describing a gateway as a means 

to connect networks and provide necessary translation);

Harry Newton, Newton’s Telecom Dictionary 362–63 (15th 

ed. 1999) (“A gateway is what it sounds like. It’s an 

entrance and exit into a communications network.”); The 

IEEE Standard Dictionary of Electrical and Electronic 

Terms 449 (6th ed. 1996) (defining a “gateway” as a device 

that connects two systems or networks). 

Considering “gateway” in the context of the claims 

and specification of the ’487 patent, one of ordinary skill 

would have understood that the inventors did not depart 

from the ordinary meaning of “gateway” with their use of 

the term “intelligent gateway.” The gateway is intelligent 

because it includes a database of information and is 

adapted to do things such as translate dialing sequences, 

deliver short messages, provide assistance, and obtain 

information for call completion. ’487 patent col. 2 ll. 33–

38, claims 10, 35, and 40. But, consistent with its ordi-
12 STARHOME GMBH v. AT&T MOBILITY LLC

nary meaning, the specification also explains that it

connects different networks. For example, when describing the services performed by the invention, the specification explains that “[t]he system providing these services is 

based upon a configuration comprising a global packet 

switch network connecting mobile networks via intelligent

gateways.” Id. col. 2 ll. 19–21. Further, in describing the 

invention, the specification discloses two main embodiments. The first—shown in Figure 1—contains a visited 

mobile network coupled to a packet-switch network via a 

single intelligent gateway. The second—shown in Figures 

3, 4, and 5—contains two mobile networks coupled to a 

packet-switch network via two intelligent gateways. 

After reading the claims and specification, one of ordinary 

skill in the art would therefore have understood that 

“intelligent gateway” carries its ordinary meaning as a 

device that connects different networks. 

Starhome relies on Figure 2 to support its proposed

construction, arguing that the figure shows an intelligent 

gateway operating within a single network, thus constituting a preferred embodiment excluded by the district 

court’s construction. If true, Starhome’s argument would 

carry force because a construction that excludes a preferred embodiment “is rarely, if ever, correct and would 

require highly persuasive evidentiary support.” Vitronics 

Corp., 90 F.3d at 1583. However, although Starhome 

correctly points out that Figure 2 does not show a connection to a packet-switch network, we disagree that it

constitutes a separate embodiment. The specification 

explains that Figure 2 is a simplified drawing of a call 

flow in accordance with the system of Figure 1. ’487 

patent col. 1 ll. 43–44, col. 3 ll. 23–29. The packet-switch 

network of Figure 1 is not needed to explain the call flow, 

and one of ordinary skill in the art would understand that 

the drawing omits it for that reason. At best, Figure 2 

inserts ambiguity as to whether the patentees intended to 

depart from the ordinary meaning of “intelligent gate-
STARHOME GMBH v. AT&T MOBILITY LLC 13

way.” But such ambiguity does not rise to the level of the 

clear intent our case law requires. See, e.g., Teleflex, Inc. 

v. Ficosa N. Am. Corp., 299 F.3d 1313, 1325 (Fed. Cir. 

2002) (“In the absence of an express intent to impart a 

novel meaning to claim terms, an inventor’s claim terms 

take on their ordinary meaning. We indulge a ‘heavy 

presumption’ that a claim term carries its ordinary and 

customary meaning.” (internal citations omitted)). Accordingly, we find nothing in the specification that indicates a clear intent to depart from the ordinary meaning 

of “intelligent gateway.” 

Starhome further argues that the doctrine of claim 

differentiation supports its proposed construction. As 

Starhome’s argument goes, unasserted claims 1 and 47 

require the intelligent gateway to connect to an external 

packet-switch network, whereas asserted claims 10 and 

40 do not. The district court’s construction, Starhome 

continues, ignores this distinction and improperly imports 

the limitation of an external packet-switch network into 

every claim. We disagree. 

The doctrine of claim differentiation is “based on the 

common sense notion that different words or phrases used 

in separate claims are presumed to indicate that the 

claims have different meanings and scope.” Karlin Tech. 

Inc. v. Surgical Dynamics, Inc., 177 F.3d 968, 971–72 

(Fed. Cir. 1999). The doctrine is not a hard and fast rule, 

but instead “a rule of thumb that does not trump the clear 

import of the specification.” Edwards Lifesciences LLC v. 

Cook Inc., 582 F.3d 1322, 1332 (Fed. Cir. 2009); see also 

Netcraft Corp. v. eBay, Inc., 549 F.3d 1394, 1400 n.1 (Fed. 

Cir. 2008) (“While claim differentiation may be helpful in 

some cases, it is just one of many tools used by courts in 

the analysis of claim terms.”). The doctrine does not 

control the outcome here. The district court’s construction 

of “intelligent gateway” requires that it transfer information to and from a “network external to the mobile 

network.” Claims 1 and 47, however, claim a specific type 
14 STARHOME GMBH v. AT&T MOBILITY LLC

of external network; namely, a packet-switch network. 

The claims differ in scope, therefore, and the district 

court’s construction neither imports limitations from one 

claim to another nor renders any claims redundant. 

To bolster their case, Defendants point to the prosecution history of a related European application. We have 

previously held that statements made before foreign 

patent offices are sometimes relevant to interpreting the 

claims. See Gillette Co. v. Energizer Holdings, Inc., 405 

F.3d 1367, 1374 (Fed. Cir. 2005) (relying on party admissions before the European Patent Office to construe the 

claims). But we have also cautioned against indiscriminate reliance on foreign file histories. See AIA Eng’g Ltd. 

v. Magotteaux Int’l S/A, 657 F.3d 1264, 1279 (Fed. Cir. 

2011) (“[T]he varying legal and procedural requirements 

for obtaining patent protection in foreign countries might 

render consideration of certain types of representations 

inappropriate for consideration in a claim construction 

analysis of a United States counterpart.” (internal quotation marks omitted)). In this case, Starhome argued in a 

related foreign application that “a gateway provides 

access to an external environment beyond the immediate 

network,” and that “the term ‘intelligent gateway’ is 

defined in this way, that is in terms of an access means 

from one network to another.” J.A. 181. Although we 

view Starhome’s statements with the requisite caution, 

they do provide yet another indication that the patentees 

did not intend to depart from the ordinary meaning of 

“intelligent gateway.” 

As noted, the district court accepted Defendants’ proposed claim construction and construed “intelligent gateway” to mean “a network element that transfers 

information to and from a mobile network and another 

network external to the mobile network.” Because, as 

discussed above, that construction is not inconsistent with 

the ordinary meaning of “gateway,” we will not disturb it. 

We have considered Starhome’s proposed construction of 
STARHOME GMBH v. AT&T MOBILITY LLC 15

“intelligent gateway,” but because it does not reflect the 

ordinary meaning of “gateway,” we conclude that it is not 

correct.

Turning to infringement, the parties stipulated that 

“the accused systems do not directly transfer information 

to and from a network external to the mobile network.” 

J.A. 7. In addition, the parties agree that the accused 

systems are not connected to an external packet-switch 

network or other external network. Appellant’s Br. 16; 

Appellee’s Br. 57. Because the term “intelligent gateway” 

requires connection to an external packet-switch network 

or other external network, there can be no infringement. 

See Dynacore Holdings Corp. v. U.S. Philips Corp., 363 

F.3d 1263, 1273 (Fed. Cir. 2004) (“To prove infringement, 

the patentee must show that the accused device meets 

each claim limitation, either literally or under the doctrine of equivalents.”). Accordingly, we affirm the district 

court’s judgment of noninfringement. 

CONCLUSION

As set forth above, we see no error in the district 

court’s construction of “intelligent gateway.” We therefore

affirm the judgment of noninfringement. 

AFFIRMED

COSTS

Each party shall bear its own costs.