US 8380183

I'll search for authoritative information on this patent and any litigation activity.

Let me verify the claim set and check for any PTAB or district court proceedings specifically naming this patent.

Search Scope and Confidence Note

I searched for the literal identifiers "8380183" and "8,380,183." Results for similar-looking numbers (e.g., 9,467,838 / "the '838 patent," 11,246,024, 7,609,402) were excluded as unrelated. Everything below is grounded in the authoritative full text of US 8,380,183 B2 (Google Patents, fetched 2026-09-24) plus corroborating search hits.

Litigation finding — no matches, with a caveat: I found no USPTO PTAB proceeding, no W.D. Tenn./E.D. Tex. docket, and no CAFC 2026 docket naming US 8,380,183. The only Brother-related infringement activity that surfaced is Flexiworld Technologies, Inc. v. Brother Industries (U.S.A.) Inc. (W.D. Tenn., filed Apr. 2022), but that case asserts Flexiworld's patents (e.g., 7,609,402; 10,140,072; 10,140,073; 10,387,087; 10,768,871) against Brother products — not the '183 patent. I could not directly query PACER or the CAFC docket system, so this is "no evidence found," not a definitive negative.

Bibliographic Summary of US 8,380,183 B2

Abstract (verbatim):

"A communication system switches a communication state from a first communication state where a communication device performs data communication and voice communication with an external device, a first phone device, and a second phone device to a second communication state to perform the voice communication between the communication device and the second phone device and the data communication between the first phone device and the external device, when the voice communication is started using the second phone device in response to a call from a communication line. The second communication state is set when a first-phone-device network ID is used for the communication device, a communication-device network ID is used for the first phone device, and a party device of the second phone device is set to a device identified with the first-phone-device network ID."

Plain-Language Overview of the Independent Claims

Claim-numbering caveat: The authoritative text I have contains the specification and a "Definitions" section that mirrors the Summary, but not a numbered claim listing. The record presents three independent claim families (communication system; communication device; phone device), consistent with the three-part Summary. I am confident these are the three independents; I flag that the exact claim numbers of the device- and phone-side independent claims cannot be confirmed from the material at hand (claim 1 is the system claim by convention and by its first-listed position, but I cannot verify that literally).

1) Communication-system claim

A wireless system of (a) a communication device connected to a telephone line — the spec's MFP 10, (b) a first phone device, and (c) a second phone device, all wirelessly linked. The MFP stores its own network ID and the first phone's network ID; the first phone stores both of those too. When a call arrives on the line and the user answers on the second phone, the system flips from a first state to a second state:

• First state: the MFP uses its own ID (so it is seen as the MFP); the first phone uses its own ID; and every other device — external device, first phone, and second phone — is set to talk to whichever device holds the MFP's network ID.
• Second state: the IDs are swapped. The MFP now uses the first phone's ID (so the MFP is recognized as the first phone); the first phone uses the MFP's ID (so the first phone is recognized as the MFP); and the second phone's party device is set to the device using the first phone's ID.

Why it matters (in plain terms): inbound voice keeps running between the MFP and the second handset, but data traffic — which is still addressed to "the MFP" by MAC/IP — is transparently re-routed to the first handset, which is now impersonating the MFP. Voice and data are physically separated onto different devices, relieving load on the MFP's single radio. Critically, no external device needs to be reconfigured, because the addressing stays the same — only which box answers to the address changes.

2) Communication-device (MFP-side) claim

A device connected to a communication line that wirelessly talks to a first and a second phone. It has:

• a wireless unit doing both data and voice;
• storage holding the communication-device's own network ID and the first phone's network ID; and
• a controller that selects which of the two IDs the device will use.

The controller switches from the first to the second state upon receiving a response signal to an incoming call from either phone. If it uses its own ID, the first state obtains (data/voice across the board). If it uses the first phone's ID and sends the second phone a command to set the device bearing the first phone's ID as its party device, the second state obtains, in which voice runs between the MFP and the second phone.

3) Phone-device (handset-side) claim

A handset wirelessly linked to a line-connected communication device. It has:

• storage holding its own phone-device network ID and the communication device's ID; and
• a controller that selects which of those two IDs the handset will use.

It switches from the first to the second state upon receiving a communication-state-changing instruction from the communication device. Using its own ID → first state (voice with the communication device). Using the communication-device's ID → second state, in which data communication is performed between the handset and an external device that addresses the holder of the communication-device ID.

Textual Discrepancy Worth Flagging

The "Definitions" rendering of the phone-device claim reads: "a phone-device controller configured to selectively set one of the communication-device network ID and the first-phone-device network ID as a network ID for the phone device" — an apparent word-substitution artifact (the communication-device claim elsewhere contains the same "first-phone-device network ID" phrasing). Read literally, the two options in the phone claim would be the communication device's ID and the first phone's ID, which conflicts with the surrounding sentence referring to the handset's own ID. I cannot resolve this from the retrieved text; a direct look at the granted claim set (USPTO PatentCenter / patentimages PDF) would be needed for an authoritative reading.

I'll search for litigation involving US patent 8380183 across patent litigation databases.

The initial searches returned results for other patents (e.g., 9,019,838; 9,467,838; 12,010,838; 8,382,186) — none for US8380183. Let me run more targeted queries to confirm whether any litigation exists for this specific patent.

Findings: Litigation Involving US Patent 8,380,183

No litigation involving U.S. Patent No. 8,380,183 was found.

I ran multiple targeted searches across patent-litigation sources (including Unified Patents-style litigation material, RPX/insight litigation documents, Docket Alarm, PTAB/USPTO records, CourtListener, and general web search). Every result returned a different patent. I did not find a single complaint, PTAB proceeding, ITC investigation, or Federal Circuit appeal in which US 8,380,183 (or its published application US 2011/0244849 A1) is the patent-in-suit, asserted patent, or patent challenged.

Important disambiguation — patents that are NOT this one

The searches repeatedly surfaced similarly-numbered patents; none of these is US 8,380,183. Be careful not to conflate them:

None of the above involves US 8,380,183.

What the record does show about US 8,380,183

• Title: "Communication system, and communication device and phone device for the same"
• Assignee: Brother Industries, Ltd. (Brother Kogyo Kabushiki Kaisha) — recorded at filing
• Inventors: Kazuhito Misumi; Sayaka Taniguchi
• Priority date: 2010-03-31 (JP App. No. 2010-082351)
• Application: US 13/072,731, filed 2011-03-27
• Grant date: 2013-02-19
• Legal status: Expired – Fee Related (anticipated expiration 2031-03-27)
• Technology: Wireless (WPAN/WLAN) MFP with interchangeable network IDs between an MFP and extension cordless phone sets; switching between a first and second communication state for voice/data separation.

The patent appears to be a dormant, never-asserted corporate portfolio asset. It does not show up in any assertion activity, and its expired-for-fee status is consistent with it having been abandoned rather than enforced.

Caveats and how to verify independently

• I could not access paywalled/comprehensive dockets (e.g., full PACER, Lex Machina, Docket Navigator, or Unified Patents' full case list) directly within these searches. My searches were limited to publicly indexed sources.
• Absence of evidence in indexed sources is strong but not absolute proof of zero litigation. A patent that was asserted and settled early, or litigated in a court whose docket is not well-indexed, could theoretically be missed.
• Recommended verification steps if you need a definitive clearance or FTO statement:
  1. Unified Patents litigation portal (https://portal.unifiedpatents.com/litigation) — search the exact number "8380183."
  2. PACER / CourtListener RECAP — search "8,380,183" and "8380183" across district court dockets.
  3. USPTO Patent Center / PTAB — the patent's "Litigation" and "Proceedings" tabs for any IPR/PGR/CBM.
  4. USITC EDIS — for any Section 337 investigation naming the patent.
  5. Lex Machina / Docket Navigator — commercial databases that are the most complete for assertion history.

Bottom line: Based strictly on the sources searched and the identifiers as given, there is no known litigation involving US Patent No. 8,380,183. I am stating this with the caveat above rather than claiming an exhaustive negative, since I could not query every paywalled docket database directly.

I'll verify the structured block's "no PTAB activity" default with independent web searches before finalizing.

The initial hits are all for other patents ending in "838" (9,019,838; 9,467,838; 12,010,838). Let me run more targeted searches on this specific patent's number, title, and assignee.

No hits specific to this patent. Let me check the Unified Patents portal and litigation databases, which aggregate PTAB challenges.

Proceedings overview

Total AIA trial proceedings on file for US 8,380,183: zero. The structured "PTAB proceedings on file" block — sourced from the USPTO Open Data Portal — returns no IPR, PGR, or CBM proceedings, and my independent web searches corroborate that result (no proceeding number, institution decision, FWD, or appeal for this patent could be located). The bottom-line defensive posture for a defendant today is therefore unusual and double-edged: 8,380,183 has never been tested at the PTAB, so no claim has been canceled or confirmed in an AIA trial. That means (a) you get a full, un-estopped, first-mover IPR opportunity if the art is there, but (b) you cannot lean on any prior PTAB outcome — there is no "claim 1 is already dead" shortcut to exploit. This is a pristine but untested 2013-grant patent, not a hardened one.

No proceedings to report

There is no IPR, PGR, or CBM number to list for US 8,380,183. Per the operating constraint against fabricating proceeding numbers, I am not populating the per-proceeding template with anything.

For diligence transparency, my searches surfaced several false positives, all of which involve different patents whose numbers merely end in "838," and none of which are US 8,380,183:

• IPR2016-00573 — instituted as to claims 1, 2, 7, 26, 29, 38, 40, 47, 55, and 69 of U.S. Patent No. 9,019,838 (De Nicolo '468 / De Nicolo '666, § 103). Different patent.
• IPR2020-00509 and related — U.S. Patent No. 8,457,228 (Siwiak art). Different patent.
• IPR2022-01349 — [Cellco Partnership d/b/a Verizon Wireless](/litigations/by-plaintiff/Cellco%20Partnership%20d%2Fb%2Fa%20Verizon%20Wireless) v. AGIS Software Development LLC, involving U.S. Patent No. 9,467,838 (Haney / Fumarolo, § 103). Different patent.
• IPR2025-00229 — Micron Technology v. YMTC, involving U.S. Patent No. 12,010,838. Different patent.
• Various Petitions referencing U.S. Patent Nos. 11,653,183 and others. Different patent.

None of these is an AIA trial on US 8,380,183, and none involves Brother Industries / Brother Kogyo Kabushiki Kaisha as patent owner of the '183 patent in the manner relevant here. I flag them only so the record shows the search was run; they must not be cited as proceedings on this patent.

Strategic summary

Claim-by-claim status of 8,380,183 (as relevant to a defendant): CANCELED — none. SUSTAINED — none. UNTESTED — all. Because no AIA trial has ever been instituted, every claim of the patent stands exactly as issued on 2013-02-19 (subject only to whatever occurred during original prosecution and any ex parte reexamination — I found no reexamination certificate for this patent either, but I cannot rule one out with high confidence from the sources available). The patent is titled "Communication system, and communication device and phone device for the same," is assigned to Brother Industries Ltd., claims priority to JP 2010-082351 (2010-03-31), and claims an October 2010 priority date vintage with described subject matter — MFP-as-routing-device, WPAN/WLAN concurrency, and swapping network IDs between an MFP and an extension phone set so a phone device transparently substitutes as the routing device during a voice call. This is networking/routing subject matter that, on its face, would be eligible for IPR and (depending on CBM-eligibility timing and the "technological invention" carve-out) potentially CBM as well, though CBM is now sunset for new petitions.

Estoppel landscape: There is no § 315(e)(2) estoppel on this patent because no IPR/PGR was instituted and no FWD issued — estoppel attaches only after a final written decision. For a defendant currently facing assertion, that is good news: nothing that "could have been raised" bars you. Every prior-art ground you can find — § 102 anticipation, § 103 obviousness, printed publications, patents, and (for IPR, only as to patents and printed publications) system-art-derived publications — is available to you in a fresh petition. You would be the first petitioner, so no § 325(d) "previously presented art" risk from an earlier PTAB record (only the original Examiner's record matters).

Pattern signals: No petitioner has taken a shot at this patent — not once. No repeat-filer pattern, no joined/consolidated IPR train. No PTAB appeal activity by the patent owner is identifiable. No defensive aggregator (Unified Patents, RPX, AST, etc.) appears in the chain for this patent; the searches returned no Unified Patents filing tied to 8,380,183. The patent is "Expired – Fee Related" per the Google Patents legal-status field (with an anticipated expiration of 2031-03-27 listed), which is worth verifying against USPTO Patent Center before you commit budget: a truly lapsed patent changes the infringement calculus immediately.

The absence of PTAB activity on a Brother-issued, proactively asserted patent family is itself a signal. If this patent has never been asserted or licensed in a way that provoked a challenge, there may simply have been no economically motivated petitioner — or the patent may be relatively low-value / already near end-of-life in practice. Either way, it means the PTAB path here is unexplored territory, not a well-trodden defense.

Recommended next steps

1. Confirm status and ownership first. Pull the current USPTO Patent Center record for US 8,380,183 (application 13/072,731) to verify the "Expired – Fee Related" legal status, the maintenance-fee history, and whether any assignment (e.g., to a shell or NPE) has been recorded since Brother. A fee-related lapse would be dispositive; do not spend IPR budget before checking this.
2. No FWD to cite. Because no final written decision exists, there is no PTAB opinion to link and quote. Do not build argument on non-existent proceedings. If your adversary's demand letter or complaint references a PTAB outcome, that reference is false or belongs to a different '838 patent — demand the correct number and treat the misstatement as leverage.
3. Run a fresh validity search now. With zero § 315(e)(2) estoppel, the entire prior-art universe is open. Focus on the 2009–2010 priority window (JP 2010-082351) and on WPAN/WLAN-concurrent, Wi-Fi Direct / "My WiFi"-type, TDMA slot-assignment, and multi-line cordless/MFP-routing art, since the specification itself concedes this framework as known (Wi-Fi Direct, My WiFi Technology, IEEE 802.11a/b/g). The specification's own admissions are a promising § 103 starting point.
4. Trial-stage mechanics, if you file. If a petition is filed and instituted, the statutory clock runs: institution decision within ~6 months of the § 314(b) deadline, and a final written decision within one year of institution (§ 316(a)(11)), extendable six months for good cause. Calendar the POPR deadline, the one-year FWD date, and any § 315(b) one-year bar running from service of a complaint on your client.
5. If you find no strong art: say so internally rather than filing a weak petition. A denied institution leaves you with no estoppel downside but costs fees and burns credibility, and a first-ever IPR that the patent owner survives would harden this patent against the next defendant.

Confidence caveat: Based on the structured ODP block plus the web searches I ran, I found no AIA trial proceeding on US 8,380,183. I could not access every closed-door registry (e.g., a full PTAB E2E docket scrape or a CourtListener docket search for a CAFC appeal) within this session, and very recently filed petitions may not yet be indexed. Treat the conclusion as "no PTAB activity on file" per the canonical source, not as an absolute metaphysical certainty.

I'll verify the assignment record and check for any post-issuance transfers.

Assignment & Ownership Reconstruction — US 8,380,183 B2

Record-retrieval note up front: I was able to corroborate the existence and content of a single assignment event for this patent from Google Patents' legal-events feed (fetched 2026-09-24), but I could not retrieve the underlying reel/frame number or the correspondent-of-record from the USPTO Assignment Center record via the sources open to me (the Assignment Center search is a JavaScript/API application and did not return a retrievable indexed record; Google Patents renders the event as "ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS)" without exposing a reel/frame). Per the operating rules, I will not invent a reel/frame or a correspondent name. Where the data is missing, I say so.

Inventors

Pattern assessment: Both inventors assigned to the same corporate employer on the day the US application was filed (2011-03-27), which is the standard employee-invention assignment executed contemporaneously with filing — not a fire-sale or departure signal. The application claims priority from JP 2010-082351 (2010-03-31), so the invention was ~12 months old at US filing.

Departure check: unclear. I found no evidence either inventor left Brother within 12 months of filing, and equally no evidence that either remained. I could not run an inventor-name cross-check across Brother's later filings in the sources available, so I make no finding here. (Flagged as unresolved rather than as a negative.)

Original assignee

Brother Kogyo Kabushiki Kaisha — the Japanese legal name of Brother Industries, Ltd. (TYO: 6448), 15-1 Naeshiro-cho, Mizuho-ku, Nagoya 467-8561, Japan.

• Primary line of business: Operating manufacturer — printers, multi-function peripherals (MFPs), fax machines, label makers, sewing machines, and machine tools. The patent's "MFP 10" is squarely a Brother product form factor (a fax/telephone-line-connected multifunction printer with cordless extension handsets).
• Product embodying the claims: Yes. The specification describes a shipping-type product — an MFP that establishes a WPAN 201 (Wi-Fi Direct / Intel My WiFi is expressly discussed) and a WLAN 202, with first and second extension phone sets 1 and 2 performing WPAN audio and data traffic. This is a real Brother MFP + cordless-handset architecture, not a paper-only claim.
• Current status: operating. Brother Industries, Ltd. is a publicly traded, solvent operating company in Nagoya. I found no Chapter 7/11 filing, no merger, and no dissolution relating to this patent's chain.

Name-variant flag (not a change of name): Google Patents lists "Original Assignee" and "Current Assignee" as Brother Industries Ltd, while the reassignment event names BROTHER KOGYO KABUSHIKI KAISHA. These are the same entity (English trading name vs. registered Japanese name). This is not a recorded Change of Name conveyance, and it should not be read as two links in the chain.

Assignment timeline

One — and only one — recorded assignment exists for this patent.

• 2011-03-27 (executed) / recorded 2011-03-27 — Reel not retrieved / Frame not retrieved
  • Conveyance: Assignment (Assignment of Assignors' Interest)
  • Assignor: Misumi, Kazuhito; Taniguchi, Sayaka
  • Assignee: Brother Kogyo Kabushiki Kaisha
  • Correspondent: Not recovered. The retrieved record does not expose the correspondent attorney/firm. Consequently I cannot state whether the recording attorney recurs elsewhere and make no "repeat correspondent" finding.
  • Context: Original corporate assignment of employee invention, executed and recorded the same day the US application 13/072,731 was filed — a routine in-house-to-employer assignment, not a post-issuance transfer.

No post-issuance assignment of any kind was found: no assignment, security agreement, merger, change of name, license, release, or correction recorded after the 2013-02-19 grant.

Post-issuance status (from Google Patents legal events, not an assignment): the record carries the status "Expired – Fee Related" with an anticipated expiration of 2031-03-27. The anticipated date is the 20-year statutory maximum; the "Expired – Fee Related" label indicates the patent lapsed early for non-payment of a maintenance fee. I could not retrieve the specific fee-window date from the record, so I do not assign a lapse year.

Consequence: Brother Industries, Ltd. is the assignee of record for the entire life of this patent, and the patent is no longer in force.

Timeline diagram

timeline
    title Ownership of US 8380183
    2010 : Japanese priority application filed
    2011 : US application 13/072,731 filed
         : Assigned to Brother Kogyo Kabushiki Kaisha
    2013 : Patent US 8380183 issued
    2020s : Record marked expired for unpaid fees

NPE / troll-pattern signals

Verdict

Insufficient data (only the original assignment)

Justification: The chain consists of a single recorded link — the 2011-03-27 assignment of Misumi and Taniguchi's interest to Brother Kogyo Kabushiki Kaisha, executed on the same day US application 13/072,731 was filed (reel/frame not retrieved; correspondent not recovered). There are no post-issuance assignments, so every NPE signal that depends on a downstream transfer (shell entity, cascading transfer, pre-litigation transfer, privateering, defensive aggregation) is structurally impossible to satisfy. The substantive non-NPE facts are that the original assignee is a solvent, product-shipping operating company and the record now carries an "Expired – Fee Related" status, which together describe a dormant, non-asserted corporate asset rather than an assertion vehicle. Because the only available evidence is the original assignment, the rubric's "Insufficient data" bucket is the correct pick rather than "Defensive / non-asserting," which presupposes a chain terminating at a defensive aggregator.

Verify independently at: https://assignmentcenter.uspto.gov/ (search patent number 8380183; the equivalent legacy interface is https://assignment.uspto.gov/patent/index.html). The one open item worth pulling from that record is the reel/frame and correspondent for the 2011-03-27 recording, which I could not retrieve.

Cross-reference notes and explicit flags

• Consistency with prior sections: This reconstruction is consistent with the earlier litigation finding (no suit, no PTAB proceeding, no ITC investigation naming US 8,380,183) and with the bibliographic table (assignee Brother; status Expired – Fee Related; anticipated expiration 2031-03-27). Nothing in the assignment record contradicts those sections.
• Minor internal tension to flag: The earlier litigation section characterized the expired-for-fee status as "consistent with it having been abandoned rather than enforced." That inference is directionally sound but should be stated carefully — "Expired – Fee Related" reflects a maintenance-fee lapse, which is a lapse event, not proof of an affirmative abandonment decision. I flag it so the two sections are not read as stating that Brother formally abandoned the patent.
• Do not conflate: As in the prior sections, similarly-numbered patents (9,019,838; 9,467,838; 12,010,838; 8,382,186; 8,867,932) appeared repeatedly in searches and are unrelated to US 8,380,183.

I'll search for the specific patent's citation record and prior art.

Interesting — I found a sibling patent in the same family. Let me dig deeper into the actual citation record of US8380183.

Let me look for the patent's citation record on USPTO/Justia/FreePatentsOnline.

Prior-Art Analysis — US 8,380,183 B2

Bottom line up front

I could not retrieve the patent's actual "References Cited" (citation) list from the sources available to me, and I will not fabricate citations to fill that gap. The authoritative Google Patents text provided for this patent contains the specification, abstract, and a "Definitions" section — but it does not include the front-page citation block (the U.S. Patent Documents / Foreign Patent Documents / Other Publications lists that the Examiner prints on the granted patent). US8380183B2's Google Patents record (fetched 2026-09-24) likewise showed "Primary reference (cited): None listed in the retrieved record."

Because 35 U.S.C. § 102 anticipation is a reference-by-reference, element-by-element exercise, I cannot truthfully complete the requested table without the citation list. Below is exactly what I can establish, plus what the record itself says about prior art, plus how to close the gap.

1. What I confirmed for US 8,380,183 B2 (literal identifier)

Citation record status: NOT RETRIEVED. The front page of the granted PDF is the authoritative source for the Examiner's cited references, and I was unable to extract it.

2. What the record itself identifies as prior art (narrative only — no numbers)

The patent's own Background section describes the state of the art it reacts against, but gives no patent numbers or document identifiers:

"A technique has been known in which one of wireless terminal devices establishes a network as a control station and the other wireless terminal devices join the network as slave stations. Further, a technique has been known in which a role as the control station is transferred from a terminal device that already serves as the control station to a slave station. In switching the control station, information such as 'the control station is to be switched,' 'a newly-set control station,' and 'a moment when the control station is to be switched' is placed in a periodically-issued beacon frame, and transmitted to all the terminal devices on the network."

This is admitted prior art by description only. It is not citable as a specific reference, and it maps only to the general concept of control-station handover via beacon frames (relevant to the "switching"/"role transfer" concept) — not to the ’183 patent's distinctive feature: interchanging MAC/IP network IDs between an MFP and an extension handset so that external devices need no reconfiguration. No § 102 mapping can be built on this narrative alone.

3. Critical disambiguation — a sibling patent exists (NOT prior art)

The search surfaced a sibling in the same Brother family that must not be mistaken for prior art:

⚠️ Flag: these appear together (with the ’183 patent) in third-party citation tables, which is a common source of confusion. Neither is available as § 102 art against US 8,380,183.

4. Why § 102 mapping cannot be completed as requested

To fill the requested "which claim(s) it potentially anticipates under § 102" column, I would need, for each cited reference: (a) its full citation, (b) its publication/filing date (to test § 102(a)/(b)/(e) status), and (c) its disclosed subject matter mapped against the elements of claim 1 (system), the communication-device independent claim, and the phone-device independent claim. I have none of the enumerated references, only the applicant's narrative background. Producing a table would mean inventing references — which the operating rules prohibit.

I also note (consistent with the earlier-generated section) that the exact independent-claim numbering is not verified from the material at hand, so even a reference-by-reference mapping would carry a claim-number caveat.

5. How to obtain the authoritative citation list (recommended, definitive)

1. Patent full-text/front page — open the granted PDF front page (patentimages.storage.googleapis.com/e9/ad/98/c253998821ca29/US8380183.pdf); the "References Cited" block lists U.S. patent documents, foreign patent documents, and other publications.
2. USPTO Patent Center (https://patentcenter.uspto.gov) — application 13/072,731; retrieve the IDS / PTO-892 (Notice of References Cited) and the issued patent front page. This is the examiner's actual art.
3. USPTO Patent Public Search (https://ppubs.uspto.gov) — search the exact number 8380183; view "Referenced By" and cited documents.
4. Google Patents — the "Citations" and "Cited By" tabs for US8380183B2 (the "Cited By" list is confirmed to exist and includes later Brother wireless-communication patents such as US 9,338,818 B2 and US 10,863,583 B2, but those are forward citations, not prior art).
5. INPADOC / EPO Espacenet for the JP priority JP 2010-082351 and the JP family's search-report citations.

6. Confidence statement

• High confidence: the bibliographic data in § 1 (literal identifiers, dates, assignee) and the fact that the retrieved authoritative text contains no citation list.
• High confidence: US 8,385,907 B2 and US 2011/0244849 A1 are family, not § 102 prior art against US 8,380,183.
• High confidence: the Background's "known technique" is described without any document identifiers.
• Cannot state, and do not assert: any specific cited reference, its date, or any § 102 anticipation mapping — because the citation record was not retrievable from the sources searched. I am stating this as a gap rather than guessing.

If you can supply the PTO-892 / front-page "References Cited" list (or authorize a Patent Center pull of application 13/072,731's file wrapper), I can immediately produce the full per-reference table you asked for — full citation, publication/filing date, brief description, and the claim-by-claim § 102 analysis.

I'll start by trying to recover the actual prior-art citations for this patent, since the fetched record showed no cited references, then locate the closest field art.

Let me look for the family's search reports and the specific field art on control-station handover and WPAN/WLAN coexistence, which is what a § 103 analysis on these claims would rest on.

Let me pin down concrete, citable references for the two inventive pillars — control-station/routing-role handover, and MFP/base-station voice-plus-data with cordless handsets.

Obviousness Analysis — US 8,380,183 B2 under 35 U.S.C. § 103

Builds on: the Bibliographic Summary, the Plain-Language Overview of the Independent Claims, the flagged "first-phone-device network ID" textual discrepancy in the phone-side claim, and the Litigation Summary (no assertion history; expired-fee status). This section does not repeat those; it takes them as inputs.

Not legal advice. This is a technical/analytical § 103 assessment, not a validity opinion or an FTO clearance. Conclusions are contingent on claim construction and on verification of the reference set against the official record.

1. Evidentiary base — and a candid limitation on it

The instruction is to use "the Prior Art section of this page." As retrieved (Google Patents, snapshot 2026-09-24), that page contained no prior-art citation list: no “Cited By,” no “References Cited (56),” no parent/continuation entries — consistent with the earlier section's note that the record lists “Primary reference (cited): None.” The page renders the specification and a "Definitions" mirror of the Summary; it does not render an IDS/892 or search report.

I therefore could not quote the examiner's/ applicant's actual cited art. Two consequences:

1. Everything below is built from (a) the applicant's own admitted background art, (b) analogous-field references I could locate and date, and (c) the legal standard. It is not the Examiner's art set.
2. To make this rigorous, pull the definitive art: (i) the file-wrapper IDS/Form PTO-892 and any Non-Final/Final § 103 rejection in US App. 13/072,731 (USPTO PatentCenter); (ii) the JP search report / decision on the priority case JP 2010-082351; and (iii) any EP counterpart search report (the family is Brother-originated). Those supply the references that actually mattered.

1.1 Governing law and timing

• Application filed 2011-03-27; priority 2010-03-31 → pre-AIA § 103(a) governs (AIA first-inventor-to-file applies to applications filed on/after 2013-03-16). The critical date for prior art is 2010-03-31.
• Standard: Graham v. John Deere factors (scope/content of art; differences; PHOSITA level; secondary considerations) as refined by KSR Int'l v. Teleflex, 550 U.S. 398 (2007) — a claimed combination is obvious if the improvement is a predictable use of prior-art elements according to their established functions, and if a POSITA would have had a reason to combine (design need, market pressure, "obvious to try" in a finite, predictable field).

1.2 PHOSITA — level of ordinary skill

A POSITA here is a wireless/telephony engineer with ~2–4 years' experience in IEEE 802.11 WLAN/WPAN coexistence and cordless/extension telephone (base + handset) systems, conversant with: (a) MAC-address/IP-address identification and address reassignment; (b) beacon-driven network control; (c) soft-AP / "group owner"-style roles where one node acts as the access point/bridge for others; and (d) real-time (voice) vs. retransmitted (data) traffic handling. The patent's own spec confirms this baseline is the relevant one — it calls the WPAN/WLAN setup, AP, and routing-device concept all "known," and invokes Wi-Fi Direct and Intel's My WiFi Technology as pre-existing proposals for making one device the network's server.

1.3 Reference datability (this is where most superficial analyses go wrong)

Several search hits look devastatingly on point but post-date the 2010-03-31 critical date and are legally unavailable as § 102/§ 103 art against this patent. They are noted here only as evidence of what the field later treated as routine, not as prior art.

Caution on a number collision (flagging per the earlier section): a hit for "US 2015/0244849 A1" surfaced in search; its claim 1 is an incoming-call allow/block and reporting apparatus — not this patent. Do not conflate it with US 2011/0244849 A1, which is the '183 pre-grant publication. This is exactly the kind of near-number contamination the earlier section warned about.

2. What is actually in dispute — the three independent claims

From the earlier Plain-Language Overview, the three independents are the system, the communication-device (MFP), and the phone-device (handset) claims. Distilled to their substantive limitations, each requires:

The only genuinely load-bearing limitations are L4–L6 — specifically the deliberate two-way ID swap plus third-device re-pointing, triggered by answering on the other handset. Everything else is established art. That is the field a § 103 rejection must occupy.

3. Primary combination (Combination I) — the strongest § 103 case

Proposed combination:

• Reference A (admitted background art): the control-station-transfer-via-beacon technique described in the patent's own Background — applicant's admission that this is prior art. Corroborated concretely by JP 2003-134040 A and US 2007/0293223 A1 / US 8,335,548 B2.
• Reference B: US 2005/0033816 A1 — master-station handover in a wireless system using network-ID/address fields and a capability-handover request packet, i.e., a node assuming a role previously held by another, with identifiers carried in the messaging.
• Reference C (admitted): Wi-Fi Direct / My WiFi Technology (soft AP / group-owner) — one device presenting itself as the AP/bridge for other devices and cross-connecting a peer group to an infrastructure BSS (the spec concedes this is known).

Claim-by-claim mapping:

Motivation to combine (KSR):

1. Same field, same problem, finite/predictable solutions. A, B, C are all wireless-network role/address management — the very art a POSITA would consult for "who serves the network."
2. Art-recognized reason for handing off the network role: US 2007/0293223 A1 expressly motivates handover by battery/power and by which terminal is best situated — i.e., offloading a role from one node to a better-suited node. Transplanting that reason to "offload the data role from the MFP's single radio while it services a real-time voice call" is the same reason applied to the same kind of decision.
3. The patent's own stated problem supplies the design need: the spec says voice is "heavier-load… required to be performed in a real-time basis," and that running voice (212) and data (213) in parallel "might result in… an error that the voice communication is interrupted and/or a lowered communication speed." A POSITA facing that admitted problem would predictably look to separate voice from data onto different nodes/radios — a known load-isolation technique.
4. Address takeover is a known, low-risk mechanism. Moving an identity so traffic transparently follows is standard practice (failover/clustering, MAC-move, proxy/virtual-MAC). Nothing in the combination produces a new or unexpected result; every element performs its established function.

Reasonable expectation of success: High — each step (detect off-hook → announce role change via beacon → move the address → notify the remaining client of the new holder) is individually known and mechanically composable. No teaching away identified.

4. Where Combination I is vulnerable — the honest gap

I do not have a reference that expressly discloses L5 in its full, literally-claimed form — i.e., a two-way exchange in which the base adopts the handset's ID and the handset adopts the base's ID, with a third terminal re-pointed accordingly. The references I could date teach role handover (A/B) and address fields in handover messaging (B), and the field understood address takeover generally; but the specific paired swap is what let this patent issue.

Accordingly, an examiner or petitioner would need one more element:

• A reference (or an obviousness rationale) teaching identity/address migration between cooperating nodes — e.g., "virtual MAC," "MAC address move," or failover art where a standby assumes the identity of a failed primary so that peers need not be reconfigured. That property — "no external device needs reconfiguring" — is asserted in the spec as the invention's advantage, but it is the built-in, expected property of address takeover, not a new mechanism. Under KSR, leveraging a known technique's known property for its known purpose is the paradigm of obviousness.

Likely applicant/reasoning rebuttals and how they fare:

5. Secondary claim families

5.1 Communication-device (MFP) claim

Adds: a controller that selects which ID the device uses, switching in response to receiving a response signal to an incoming call from either handset, and sending handset-2 a command to set its party device to the first phone's ID.

• "Selectively set one of two stored network IDs" → routine address assignment (Reference B's ID field; ordinary config).
• "Trigger = response signal to an incoming call" → off-hook/answer signaling is ubiquitous in cordless telephony (the base inherently knows which handset answered). Predictable.
• "Send a command to a peer to set its party device" → the handover-announcement function of Reference A (beacon) and B. Predictable.
  → Obvious over A + B + cordless-telephony off-hook art, for the same reasons.

5.2 Phone-device (handset) claim

Adds: storage of its own ID and the communication device's ID; a controller selecting between them; switching on a communication-state-changing instruction; own-ID → voice with the base; base-ID → data with an external device that addresses the base's ID.

• The handset adopting the base's identity to receive traffic destined for the base is, again, address takeover by the idle node.
• ★ Re-flag the textual defect: as rendered on the page, this claim recites selecting between "the communication-device network ID and the first-phone-device network ID," which conflicts with the surrounding "its own ID" language (the earlier section flagged this). For any § 103 challenge, obtain the granted claim text (USPTO PatentCenter / patentimages PDF) before relying on the literal scope. If the granted claim literally pairs the base's ID with "the first-phone's ID," the claim is both internally inconsistent and, read one way, covers only the two-device identity swap — which is not narrowed by the "own ID" reading and may actually broaden the identity-swap exposure.
  → Obvious for the same reasons; the surviving point of novelty is L5, addressed in § 4.

6. Bottom line

1. No single reference anticipates the independent claims — this is properly a § 103 matter, not § 102.
2. The claims are substantially a combination of admitted art (the applicant's own Background concedes beacon-based control-station transfer, WPAN/WLAN coexistence, Wi-Fi Direct/My WiFi soft-AP, and the MFP routing-device concept) with routine mechanisms (address/ID storage and selection, off-hook detection, handover announcements, address takeover).
3. A strong prima facie § 103 case exists for all three independent families via Combination I (admitted background art JP 2003-134040 A / US 2007/0293223 A1 + US 2005/0033816 A1 + admitted soft-AP/group-owner art), with the stated design need (voice/data load separation) supplying motivation and address takeover supplying the mechanism.
4. The case is not airtight. It hinges on bridging L5 — the deliberate two-way ID swap — with pre-2010 identity-migration/failover art, which I could not pin to a specific reference in this session. Without that bridge, a well-argued non-obviousness position survives on the asserted transparency advantage and the "answer-on-second-handset-triggers-first-handset-takeover" arrangement.
5. Excluded and flagged: US 2011/0225305 A1, US 2011/0149816 A1, US 2015/0264123 A1 / US 9,532,193, US 2015/0110090 A1, US 2014/0068719 A1, US 11,057,360 all post-date the 2010-03-31 critical date and are not § 103 art here; and US 2015/0244849 A1 ≠ US 2011/0244849 A1.

Next verification steps to convert this into a defensible opinion: (i) retrieve the IDS/892 and any § 103 rejection from US App. 13/072,731; (ii) retrieve the JP search report / decision for JP 2010-082351; (iii) obtain the granted claim text to resolve the flagged ID-substitution artifact; (iv) search specifically for pre-2010 "virtual MAC / MAC move / failover address takeover" art to bridge limitation L5.