US 4652700

I'll run several searches to ground this analysis.

Let me search specifically for the claim text and any 2026 litigation.

Let me try to retrieve the actual claim text and check for any litigation activity.

1. What I searched and what I could retrieve

I ran targeted searches against Google Patents, USPTO/PTAB document repositories, and general web indexes for the literal strings US4652700, 4,652,700, and combinations with the title, inventors, and assignee. Results below are limited by an important gap: the patent record fetched into this analysis truncates in the middle of the description (at the FIG. 12 flow-chart text) and does not include the claims. I therefore cannot quote claim language verbatim, and I flag inferred content accordingly.

2. Bibliographic record (from the fetched US4652700A / Google Patents record)

Data-quality caveats (no auto-correction applied): the reassignment entries on the record are internally out of chronological order — a 2002-03-26 entry names Octel as assignor to Lucent, while a 2006-06-29 entry names VMX as assignor to Octel. I am reporting these literally as listed rather than reconciling them. Likewise, the priority claim runs back to a 1979 application even though the '700 filing date is 1982.

3. Abstract

I did not retrieve the verbatim official abstract text from the USPTO website — Google Patents' rendition of this record did not surface the abstract block in the returned content. The closest verbatim abstract-like language available in the fetched specification's own summary is:

"...the present invention described and disclosed herein comprises a method and apparatus for receiving storing and forwarding analog information from a user's telephone facility... the apparatus comprises an electronic digital signal processor for controlling the operation of the message system and a digital memory controlled by the signal processor for storing digital representations of the analog information... the analog information comprises a first part for routing to selected recipients telephone stations and a second portion for defining route data."

Treat this as specification language, not a certified abstract quotation. Anyone needing the certified abstract should pull it directly from USPTO Patent Center or the printed front page.

4. Plain-language overview of the independent claims

Confidence: LOW — inferred, not read. The claim set is not present in the material I have. The following is inferred from the specification's "Summary"-style paragraphs and the feature flow charts (FIGS. 30–46). Do not rely on this as a claim construction.

What the disclosure supports (verbatim from the spec's summary passages):

• A method-and-apparatus pair for receiving, storing and forwarding analog information from a user's telephone facility, using an electronic digital signal processor controlling the system and a digital memory storing digital representations of the analog information.
• Address/routing structure: the analog information is divided into a "first portion" for routing to selected recipients' telephone stations and a "second portion" defining route data. The system is accessed by signals over the telephone facility; the stored information is reproduced in analog form and sequentially transmitted to the selected recipients; and the first portion is automatically deleted after transmission.
• An outside-access / answer-delay feature: a detecting circuit detects an attempted access to the system from outside the user's facility, checks for stored information associated with the attempted access, and if none is present, delays answering for a predetermined interval (this maps to the "DID answer delay" feature, FIG. 43).
• A facsimile feature: the analog information may contain facsimile information comprising tone signals representing coded information, stored digitally and reproduced by transmission to the accessing user; a FAX machine converts graphic information to analog form under user control for digitization and later delivery (FIG. 44).

The specification also describes numerous features that likely appear in dependent claims or in the CIP-added disclosure: message deposit/delivery with user-ID validation, addressee processing, group/distribution-list codes and user-changeable group codes (FIG. 31), redirect and reply/save special-function codes, automatic variable time scan (FIG. 32), quiet-time compression (FIG. 33), message edit (FIG. 34), DID/ICH (FIG. 35), recorded-outcalling message address recording and access (FIGS. 36–37), personal information message (FIG. 38), interactive voice message system (FIG. 39), sequential group calling (FIG. 41), status check (FIG. 42), analog networking (FIG. 45) and hybrid networking (FIG. 46) — the latter two being the VMS-to-VMS networking arrangement of FIG. 2 routed over MODEM links or the public telephone network.

If exact claim language matters, it must be pulled from the granted patent's claim set (USPTO Patent Center / the printed '700 patent), which I could not retrieve.

5. CAFC 2026 docket / USPTO litigation check

Searches for a Court of Appeals for the Federal Circuit 2026 docket involving patent 4652700 returned no results. This is consistent with the record: the patent's anticipated expiration was 2004-03-24, so it has been expired for roughly two decades and cannot support a live 2026 infringement action. I found no 2026 PTAB, district court, or CAFC activity for this number, and I make no claim that none exists — only that my searches did not surface any, and the expiry status makes such activity implausible.

6. Uncertainty summary

• High confidence: patent number, title, inventors, application number, filing date, priority date/relationship to US 4,371,752, grant date, assignee chain as listed, expired status, classifications.
• Medium confidence: the abstract — the content is grounded in the specification, but I did not retrieve the certified abstract text.
• Low confidence / explicitly flagged: the independent-claim overview. The fetched record ends mid-description and contains no claims; my claim summary is a reasonable reading of the specification's summary paragraphs and feature figures, and should be verified against the granted claims before being used for any substantive purpose.

I'll research litigation involving US patent 4652700 across patent litigation sources.

Let me search more targeted litigation sources.

The results so far are mostly noise. Let me search more specifically on the patent holder and known voice-mail patent campaigns.

Summary answer

I found no litigation — asserted or declaratory — naming U.S. Patent No. 4,652,700. With the caveat that I was cut off partway through my searches (my tool budget ran out mid-research), the sources I was able to check surfaced no case in which the '700 patent was the patent-in-suit, and the patent itself is long expired, so no new cases are possible.

What the patent is (for identification purposes only)

• US 4,652,700 — "Electronic audio communications system with versatile user accessibility"
• Inventors: Gordon H. Matthews; Thomas B. Tansil; Michael L. Fannin
• Original assignee: VMX, Inc. (Dallas, Tex.)
• Application No. 06/428,243, filed Sept. 29, 1982; granted Mar. 24, 1987
• Priority claim (CIP) from US 06/097,240, priority date Nov. 26, 1979
• 6 claims, 71 drawing figures
• Later chain of title: ECS Telecommunications → VMX Inc. → Octel Communications → Lucent Technologies → Avaya Technology LLC
• Status: Expired – Lifetime; anticipated expiration Mar. 24, 2004

This is the second-generation VMX voice-mail patent. It descends from the same 1979 priority family as US 4,371,752 ("Electronic audio communications system with versatile user accessibility" / the Tansil–Matthews voice-messaging patent), which is the patent that actually drove VMX's licensing and enforcement activity.

Litigation I was able to find (and why it is not '700 litigation)

1. Voice Systems and Services, Inc. v. VMX, Inc.

• Source: Markman/opinion order dated Nov. 5, 1992, mirrored at the UNH IP Mall Markman archive: https://ipmall.law.unh.edu/sites/default/files/hosted_resources/Markman/pdfFiles/1992.11.05_VOICE_SYSTEMS_AND_SERVICES_INC_v._VMX_INC.pdf
• Plaintiff/counter-defendant: Voice Systems and Services, Inc. ("VSSI"), maker of the "Communicator" voice mail / automated attendant product
• Defendant/counterclaimant: VMX, Inc.
• Patents actually at issue: U.S. 4,371,752 (voice mail), U.S. 4,722,124 and U.S. 4,783,796 (automated attendant). The court expressly identified these three; the '700 patent is not mentioned in the opinion. The court found VSSI infringed, and noted "the validity of VMX's patents has not been challenged in this case."
• Jurisdiction / case number / filing date / final outcome: ⚠️ I do not have these confirmed. The hosted document does not display a court caption, docket number, or filing date in the excerpt I retrieved, and I was unable to run a follow-up docket search before my searches were terminated. I will not guess at a district or docket number — that would be fabrication. This can be verified on PACER / CourtListener / the IP Mall source above.

2. VMX pre-suit enforcement campaign against IBM, AT&T, and Wang

• Reported in the Wikipedia "Voicemail" article (archived versions: https://web.archive.org/web/20230318011157/https://en.wikipedia.org/wiki/Voicemail):
  • VMX asserted infringement ("first with IBM, AT&T and then Wang"), resolving via settlements in which IBM, Wang, and AT&T each received royalty-free licenses to all VMX patents (Wang reportedly paid ~$20,000 plus a cross-license of applications).
  • VMX also settled with Octel Communications — small payment, plus Octel's agreement not to litigate any VMX patent, in exchange for a paid-up royalty-free license to all existing and future VMX patents.
  • The Wikipedia account states "The patent was never challenged in court."
• Important caveat: these were licensing/settlement assertions, not filed lawsuits, and the secondary source does not specify which VMX patent(s) were asserted. The surrounding narrative and the VSSI opinion point to the '752 voice-mail patent as the workhorse. I have no source linking these assertions to the '700 patent. Wikipedia is also an unreliable secondary source; treat it as a lead, not proof.

Negative findings and corroborating indicators

1. Google Patents has no litigation entry for US4652700A. The Google Patents page (https://patents.google.com/patent/US4652700A/en) for this patent lists only assignee reassignments — no "Litigation" section, no "Cited By" case data appearing in the fetched text. Google Patents typically surfaces litigation where it exists in its data.
2. No hits on the specific number in litigation-document repositories. Searches aimed at RPX Insight (insight.rpxcorp.com), CourtListener, and generic patent-litigation phrases returned results for other patents (the '900 patent asserted by Philip Jackson against Glenayre/Metrocall/Arch Wireless; Klausner Technologies' visual-voicemail patents; Estech's '684/'699/'349 VoIP voice-mail patents; VoiceFill's '740 patent) — none of them the '700.
3. Only incidental, non-litigation mentions of the number were found: a WO 1990/003074 search-report family listing (US-A-4652700, published 24-03-87) and an unrelated Korean nucleotide-sequence document that happens to contain the string "4652700." Neither is litigation.
4. Terminal expiry. Anticipated expiration was Mar. 24, 2004. Even if an old case existed, no live controversy on the '700 can exist today.

What I could not do (and how to close the gap)

My research was truncated by a tool-step limit before I could query:

• Unified Patents litigation portal — https://portal.unifiedpatents.com/litigation/caselist
• PACER and CourtListener/RECAP full-text docket search for the patent number
• RPX Insight patent-level litigation pages
• Historical pre-1995 district court dockets, which are poorly digitized — a real limitation here, since VMX's active enforcement period was 1985–1993

Practical next steps for a definitive answer:

1. Query Unified Patents and RPX Insight "/patents/4652700" pages directly.
2. Run a CourtListener/RECAP search for "4,652,700" and "4652700" in complaint text.
3. Pull the VSSI v. VMX docket via PACER to confirm jurisdiction, case number, filing date, and final judgment — and to confirm the '700 was not pleaded (the 1992 opinion suggests it was not).
4. For pre-digital dockets, a commercial service (Darts-IP, Lex Machina, Derwent LitAlert) is needed.

Bottom line

• Known litigation on US 4,652,700: none found. I am not asserting it definitively, but on the record available to me there is no case — asserted or declaratory — in which the '700 patent was the patent-in-suit.
• Litigation frequently associated with the same family and patentee, but involving different patents, is Voice Systems and Services, Inc. v. VMX, Inc. (1992; patents-in-suit: US 4,371,752, US 4,722,124, US 4,783,796 — VMX prevailed on infringement; validity not challenged). Docket metadata unverified.
• VMX's IBM/AT&T/Wang/Octel assertions were settled licenses, not filed suits, and are not documented as '700 assertions.
• The '700 patent expired March 24, 2004 and is now in the public domain regardless of any historical dispute.

PTAB proceedings overview

Total AIA trial proceedings on US 4,652,700: 0. No IPRs, no PGRs, no CBM reviews — nothing instituted, nothing denied, nothing settled, nothing appealed. The USPTO Open Data Portal returns an empty proceeding list for this patent, and independent web searching (Google Patents' "litigation/PTAB" cross-references, PTAB E2E document hits, and secondary docket aggregators) surfaced no AIA trial number tied to either 4,652,700 or its family members. The bottom-line defensive posture is therefore not "hardened by surviving IPRs" — it is "un-challenged and long dead." The patent's term expired on 2004-03-24, roughly eight years before the first IPR was ever filed under the AIA. There is no PTAB record to defend against, and no § 315(e)(2) estoppel burdening anyone.

A caveat on framing: the absence of PTAB activity here is not the usual "well-asserted patent that nobody bothered to challenge" signal. It is a consequence of timing — the patent expired before the AIA trial regime existed. That distinction matters for how you read the record below.

No proceeding entries

Because the structured feed contains zero proceedings and no AIA trial number for this patent could be located, I am not generating per-proceeding ### {PROCEEDING_NUMBER} sections. Inventing case numbers, panels, or claim-level dispositions would violate the core constraint of this task. Stating the negative is the accurate answer.

What the record does show (non-PTAB context only, clearly labeled):

• Patent term. Filed 1982-09-29 (App. No. 06/428,243), granted 1987-03-24, 17-year term from grant → anticipated expiration 2004-03-24 (Google Patents structured data; the patent's priority date of 1979-11-26 traces to App. No. 06/097,240, which issued as US 4,371,752). Source: https://patents.google.com/patent/[US4652700A](/patent/US4652700A)/en
• Assignment chain. VMX, Inc. (originally ECS Telecommunications, Inc., renamed VMX effective 1982-11-01) → Octel Communications Corp. → Lucent Technologies Inc. → Avaya Technology LLC (current assignee of record). Note the chain runs through legitimate telecom operating companies, not a litigation-only NPE shell.
• District court litigation, not PTAB. Voice Systems and Services, Inc. v. VMX, Inc. — a 1990s infringement action in which VMX asserted its voice-mail and automated-attendant patents. The court's 1992-11-05 claim-construction findings address U.S. Patent Nos. 4,371,752 and 4,783,796 (claims 1 and 21 of the '752 patent; claim 5 of the '796 patent) — not the claims of 4,652,700. The opinion expressly records: "The validity of VMX's patents has not been challenged in this case." Public copy: https://ipmall.law.unh.edu/sites/default/files/hosted_resources/Markman/pdfFiles/1992.11.05_VOICE_SYSTEMS_AND_SERVICES_INC_v._VMX_INC.pdf — this is a district court Markman record, not an AIA trial, and it says nothing about 4,652,700's claim scope.
• No ex parte or inter partes reexamination of 4,652,700 located in the public record either. (Inter partes reexamination existed pre-AIA but is a different vehicle from an AIA trial and is outside the scope of this task; flagging only for completeness.)

Strategic summary

Canceled vs. sustained vs. untested claims. With zero PTAB proceedings, no claim of 4,652,700 has been canceled, confirmed, or even construed by the Board. Every claim is untested at the PTAB. That is not a favorable posture for the patent owner in any practical sense, because the reason is expiration, not vindication. Because US 4,652,700A issued from an application filed 1982-09-29 and expired 2004-03-24, its claims have not been enforceable against anyone for over two decades. Any damages theory would be limited by the statute of limitations of 35 U.S.C. § 286 (six-year lookback from filing), which for an infringement that ended at expiration in 2004 ran out in 2010. There is no live infringement exposure to defend against.

Estoppel landscape. Section 315(e)(2) estoppel attaches only to a petitioner that obtained a final written decision. No FWD exists for this patent, so no estoppel runs against anyone. A defendant today faces no restriction on which prior-art grounds it may raise in district court — § 102 and § 103 art, on-sale and public-use art, printed publications, prior systems (VMX's own commercial VMS product line and its 1979 priority application are themselves candidates), all remain available. Separately, the patent's 1987 publication date means the entire specification is now a printed publication that can be used against any later patents in the voice-messaging space — which is likely why the reference appears in the prosecution histories of numerous subsequent voice-mail and messaging applications (Google Patents shows it cited against, inter alia, US 6,434,223 and US 6,545,589).

Pattern signals. No repeat petitioner (there is no petitioner at all). No PTAB appeals because there were no PTAB decisions to appeal — no Federal Circuit docket exists for this patent. No defensive aggregator involvement (Unified Patents and similar entities focus on actively asserted patents; no indication of activity here). The patent owner's enforcement history appears confined to the 1990s VMX/vendor litigation, which targeted competitor equipment makers rather than end users, and which did not put validity at issue.

Recommended next steps

• If you received a demand or notice letter asserting US 4,652,700 today, treat the claim itself as the first issue, not the prior art. Under 35 U.S.C. § 154 and the term rules, this patent expired on 2004-03-24 (17 years from the 1987-03-24 grant date, confirmed in the structured data at https://patents.google.com/patent/US4652700A/en). An expired patent cannot be infringed prospectively, and any retrospective damages window under § 286 closed in 2010. Ask the sender for (a) a certified copy of any reassignment recorded after the last Avaya-related entry at the USPTO Assignment Center, and (b) the specific § 286 damages period they believe is still open. Also sanity-check the number — demand letters occasionally mis-cite "4,652,700" for later VMX/Octel/Avaya voice-messaging patents, and the '700 claims are not the claims any 1990s court construed.
• There is no PTAB milestone calendar to track. No institution decision deadline, no oral hearing, no statutory one-year FWD due date, because no petition exists. Any representation that a live IPR or CBM on this patent is pending should be independently verified at USPTO PTAB E2E (https://ptacts.uspto.gov/ptab-ui/) and against the ODP trial-proceedings feed before you rely on it.
• Preserve your invalidity positions without estoppel worry. Since no FWD issued against anyone, no § 315(e)(2) bar applies to you or your privies. If you are nonetheless forced into a declaratory-judgment posture, the strongest non-PTAB move is a § 101/§ 112 challenge at the claim-construction and summary-judgment stage, or a motion to dismiss on the ground that the asserted patent is expired and no recoverable damages exist — not an IPR.
• Verify, don't assume. If an adversary asserts that this patent "survived IPRs" or "was confirmed by the PTAB," that statement is unsupported. Nothing on file supports it. I could not find any AIA trial number, panel, or decision for US 4,652,700, and the structured USPTO data in this prompt reports none. Treat the absence of PTAB activity as the accurate record, with the timing explanation (pre-AIA expiration) noted above.

I'll start by pulling what I can verify from live sources before assembling the chain, since the authoritative patent text provided does not include reel/frame numbers.

Let me cross-check the corporate-history events and any assertion activity for this patent.

Ownership & Assignment Analysis — US 4652700

Data-access note (important, read first). The authoritative patent record supplied for this patent (Google Patents legal-events block) lists conveyance type, assignor, assignee, and recording dates but contains no reel/frame numbers and no correspondent-of-record. My live searches (Assignment Center is a JavaScript application that cannot be crawled via the search tool; the USPTO assignment index and third-party mirrors did not return reel/frame data for this specific patent) did not surface reel/frame or correspondent fields for US 4652700. I therefore do not fabricate reel/frame numbers or attorney names — where those fields are unavailable I say so explicitly rather than filling them in. Everything below is grounded in the patent text provided plus corporate-history sources cited inline.

Inventors

Unusual-pattern check: Not present. All three inventors assigned to the employer at filing. Matthews is documented as leaving VMX only in 1989 — roughly seven years after filing, and after "the company hit rough financial waters" (Dallas Business Journal, 1998) — not the sub‑12‑month mass departure that signals a portfolio fire-sale.

Original assignee

VMX Inc. (a Delaware corporation; formerly ECS Telecommunications, Inc.), Dallas, Texas.

• Shipped a product embodying the claims: Yes. The specification describes the "Voice Message System" (VMS) — a microprocessor‑controlled voice‑message store‑and‑forward platform built from Universal Control Boards — and VMX commercialized exactly this line ("VMX was … a $100M+ revenue public company", MarketScreener/Ladd bio). This is an operating company, not a paper owner.
• Primary line of business: Voice‑messaging / voice‑processing systems for PBX and central‑office environments.
• Current status: Acquired / dissolved as an independent entity. VMX merged with Opcom in 1988 (surviving name VMX), then Octel Communications acquired VMX in 1994 (SEC 10‑K, Octel Communications, 1995), and Lucent Technologies acquired Octel in 1997 for ~$1.8B (LA Times 1997). Lucent's enterprise unit was spun out as Avaya in 2000; Google Patents lists the current assignee as Avaya Technology LLC, with the recorded Avaya entity being Avaya Technology Corp. (the source misspells it "AVAYA TECHONOLGY CORP.").

Assignment timeline

Reel/Frame and Correspondent could not be retrieved from the sources available to me (see data-access note). Recording dates below are the USPTO‑recorded dates as reflected in the patent record; execution dates for the merger links are corporate‑event dates, not verified assignment execution dates, and are flagged as such.

• 1982‑09‑29 (executed) / recorded 1982‑09‑29 — Reel unavailable / not in retrieved record

  • Conveyance: Assignment of assignors' interest
  • Assignor: Gordon H. Matthews; Thomas B. Tansil; Michael L. Fannin
  • Assignee: ECS Telecommunications, Inc. (a Delaware corporation)
  • Correspondent: not in retrieved record — do not attribute
  • Context: Initial inventor‑to‑employer assignment at filing.

• 1982‑11‑01 (effective) / recorded 1982‑12‑20 — Reel unavailable

  • Conveyance: Change of Name (record explicitly states "CHANGE OF NAME … EFFECTIVE DATE NOV. 1, 1982")
  • Assignor: ECS Telecommunications, Inc.
  • Assignee: VMX Inc. (a Delaware corporation)
  • Correspondent: not in retrieved record
  • Context: Internal rename only — no change in beneficial ownership.

• ~1994 (corporate merger; execution date not verified) / recorded 2006‑06‑29 — Reel unavailable

  • Conveyance: Merger
  • Assignor: VMX, Inc.
  • Assignee: Octel Communications Corporation
  • Correspondent: not in retrieved record
  • Context: Acquisition — Octel/VMS merger announced/perfected 1994. Note the 12‑year gap between the corporate event and recordation, consistent with a later title‑cleanup sweep.

• ~1997 (corporate acquisition; execution date not verified) / recorded 2002‑03‑26 — Reel unavailable

  • Conveyance: Merger
  • Assignor: Octel Communications Corporation
  • Assignee: Lucent Technologies Inc.
  • Correspondent: not in retrieved record
  • Context: Acquisition — Lucent's ~$1.8B cash purchase of Octel, July 1997.

• ~2000–2002 (spin‑out; execution date not verified) / recorded 2002‑03‑26 — Reel unavailable

  • Conveyance: Assignment of assignors' interest
  • Assignor: Lucent Technologies Inc.
  • Assignee: Avaya Technology Corp.
  • Correspondent: not in retrieved record
  • Context: Internal reorganization — transfer to the spun‑out enterprise‑communications entity (Avaya). Same‑day recordation as the Octel→Lucent merger entry is consistent with a single bulk title‑cleanup filing.

• 2002‑04‑09 (executed) / recorded 2002‑04‑09 — Reel unavailable

  • Conveyance: Security Interest (Security Agreement)
  • Assignor: Avaya Technology Corp.
  • Assignee: The Bank of New York
  • Correspondent: not in retrieved record
  • Context: Securitization / collateral grant to a secured lender — not an ownership transfer; Avaya retained title.

• 2004‑03‑24 — Patent term expired (anticipated expiration, 17 years from the 1987‑03‑24 grant).

• 2006‑06‑29 — VMX→Octel merger recordation (above); final recorded event in the chain.

If the Assignment Center yields no additional post‑issuance records beyond the above for your search, that is consistent with what is shown here: the last recorded owner of record is Avaya Technology Corp. (now listed as Avaya Technology LLC), subject to The Bank of New York's security interest.

Timeline diagram

timeline
    title Ownership of US 4652700
    1979 : Priority application filed
    1982 : Filed by ECS Telecommunications
         : Inventors assign to ECS
         : ECS renamed VMX Inc
    1987 : Patent issued to VMX Inc
    1994 : VMX merged into Octel Communications
    1997 : Octel acquired by Lucent Technologies
    2000 : Avaya spun out of Lucent
    2002 : Assigned to Avaya Technology Corp
         : Security interest to Bank of New York
    2004 : Patent term expired
    2006 : VMX to Octel merger recorded

NPE / troll-pattern signals

1. Shell-entity transfer — not present. Every transferee is an operating voice/telecom company (VMX → Octel → Lucent → Avaya). No "IP / Patents / Licensing / Holdings / Ventures" naming; no registered‑agent address; no single‑purpose LLC. Avaya Technology Corp. is a corporate IP subsidiary of an operating equipment maker, but there is no evidence it is licensing‑only, and a non‑operating subsidiary alone is not a finding.

2. Known asserter in the chain — not present. No transfer to Acacia, Marathon, Intellectual Ventures, IPNav, Wi‑LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp., or any Spangenberg entity. No such name appears in the assignee history.

3. Repeat correspondent across the chain — unclear / cannot be assessed. This is the field most diagnostic of NPE orchestration, and it is not present in the retrieved record. I did not obtain any correspondent attorney or recording firm for any link, so I can neither confirm nor exclude recurrence. Flagging as a genuine data gap rather than a negative finding.

4. Cascading transfers (<24 months) — not present. Transfers are separated by years, not months: 1982 (assignment + rename) → 1994 → 1997 → 2002 → 2006. There is no chained‑LLC cascade.

5. Pre-litigation transfer — not present. No infringement suit naming US 4652700 was surfaced in searches. No assignment is dated within 6 months of any assertion.

6. Bankruptcy fire‑sale — not present (for this patent). No Chapter 7/11 sale of this patent is evidenced. Avaya did later restructure (Chapter 11 in 2017 and 2023), but this patent expired 2004‑03‑24, well before those proceedings, and there is no record of it being sold in them.

7. Privateering — not present. No operating company‑to‑NPE transfer followed by assertion against competitors; the Octel/Lucent/Avaya transfers are ordinary M&A/spin‑out events.

8. Defensive aggregator — not present. The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN. It terminates at an operating company plus a bank security interest.

Verdict

Defensive / non-asserting — nearest applicable label, with caveat.

Justification (2–3 sentences): The recorded chain runs ECS Telecommunications → VMX Inc. (change of name, effective 1982‑11‑01) → Octel Communications (merger) → Lucent Technologies (merger) → Avaya Technology Corp. (2002‑03‑26), i.e., exclusively operating voice/telecom companies, with the only non‑ownership event being a security interest to The Bank of New York recorded 2002‑04‑09 — there is no assignment to any licensing‑only entity and no entity on any public NPE list. All eight NPE signals are absent or unassessable (signal 3, the correspondent field, is a data gap), and the patent expired 2004‑03‑24 unasserted. Strictly, no defensive aggregator appears, so the parenthetical definition of this verdict ("chain terminates at a defensive aggregator") is not met; I select it because it is the only non‑NPE category whose name reflects the actual disposition — a patent that was never asserted and is now expired. If you require the formal criterion, the honest call is that the supplied taxonomy lacks a "non‑asserting operating‑company" bucket, and the NPE categories do not apply.

Verify at: USPTO Assignment Center — https://assignmentcenter.uspto.gov/ (search US 4652700); patent record — https://patents.google.com/patent/US4652700/en

Recommended follow‑up to close the gaps I could not fill: (a) pull the reel/frame numbers and the correspondent of record for each of the six recorded events directly in Assignment Center; (b) treat the 2006‑06‑29 VMX→Octel recordation (12 years after the 1994 merger) and the paired 2002‑03‑26 Lucent/Octel filings as a single bulk title‑cleanup — confirm the recording attorney, since a single firm handling all six would be the one true repeat‑correspondent signal worth checking here.

I'll search for the specific patent and its cited references.

Let me dig specifically for the front-page "References Cited" listing.

Let me try patent databases that render the front-page citation list.

Important scope note before the analysis

I hit my tool-call budget on this task, so I want to be explicit about what I did and did not retrieve rather than pad the answer.

Date discrepancy (flagged, not auto-corrected): this task states "Current Date: April 26, 2026," while the system context for this session says today is 2026-09-28. I'm reporting both literally; they don't affect anything substantive here.

The critical limitation: I could not retrieve the authoritative front-page [56] References Cited block for US 4,652,700. Google Patents truncated the record at the description/flow-charts (as noted in the earlier section), and my searches surfaced the family's and third parties' citation lists — not the '700 patent's own examiner-cited art. Everything in Section 3 below is therefore labeled by source and confidence. I am not going to invent a [56] list. Section 5 tells you exactly where to pull it.

1. Patent identification (literal, verified)

I confirmed no other patent number was substituted: every database hit returned 4,652,700 with the VMX/Matthews bibliographic signature. (Search engines do suggest numeric neighbors — e.g., 4,640,991 "Electronic audio communications systems network," also Matthews/VMX — but that is a distinct family member, not a mis-hit for 4652700.)

2. What the retrieval did show about citations

The fetches returned three distinct citation datasets, which must not be conflated:

1. The '700's Google Patents "prior art keywords" — user, message, program, input, signal (metadata only; no reference list).
2. Family/interference-style cross-citations among VMX patents (e.g., the "Cited By" tables rendered on Google Patents pages for US 4,229,624 and US 4,230,906 list US4652700A, US4757525A, US4761807A, etc.).
3. Third-party citation lists that merely mention US4652700 (e.g., the US 4,994,926 Audiofax reference list, Justia's United Messaging list, the WO 90/03074 family annex). These are forward citations — later patents citing the '700 — and are the opposite of "prior art."

None of these is the '700's own backward citation list.

3. Most relevant prior art — by source and confidence

A. The priority/parent document (highest relevance, but not statutory prior art)

US 4,371,752 A — Matthews et al., "Electronic audio communication system," filed 1979-11-26, granted 1983-02-01, assignee ECS Telecommunications, Inc.
URL: https://patents.google.com/patent/[US4371752A](/patent/US4371752A)/en

• Description: The original VMX voice-message disclosure — deposit, storage, and delivery of audio messages under digital signal processor control, with user access and addressee routing.
• Claim-mapping: The '700 is a continuation-in-part of the '752's application. Every independent claim of the '700 that reads on the '752's disclosure is supported by the shared 1979-11-26 priority date.
• § 102 assessment — important negative: I do not believe the '752 anticipates the '700's claims under § 102. It shares the same inventive entity (Matthews/Tansil/Fannin) and the same common ownership, so it is not a "patent… by another" (§ 102(a)/(e) pre-AIA), and it did not issue until 1983-02-01, after the '700's 1982-09-29 filing. It is a priority document, not an anticipatory reference. Treating it as § 102 art would be an error.
• Confidence: HIGH on the bibliographic relationship.

B. The most probative prior art found — from the counterpart EP search report (same disclosure)

These were cited by the EPO examiner as X (particular relevance) against claim 1 of the European counterpart EP 0 341 800 / EP 89 20 1740 (same VMX disclosure, published 15.11.1989, Bulletin 89/46). Source PDF: http://data.epo.org/publication-server/rest/v1.2/patents/EP0341800NWA3/document.pdf

While this is the EP search report and not the '700's [56] list, it is the closest thing to an examiner's § 102 analysis of this exact specification, and is the best available basis for identifying the most relevant art.

B-1. A.J. Lincoln, "User interface design for digital voice mail systems"

• Full citation: 1982 International Zurich Seminar on Digital Communications, Zurich, 9–11 March 1982, pp. 63–67, IEEE, New York, US (paper by A.J. Lincoln).
• Dates: published March 1982 — i.e., before the '700's 1982-09-29 filing date (though after its 1979-11-26 priority date — a § 102(a)/(b)-vs-priority-date problem worth careful attention, since the CIP-added subject matter only gets the 1982 date).
• Brief description: design of the user interface for a digital voice mail system — greeting/prompt sequences and user interaction for depositing and retrieving voice messages.
• Claim(s) potentially anticipated under § 102: cited X against EP claim 1, specifically column-level citation to p. 66, left column, lines 51–60. The same passage was cited only A (background) against EP claim 3.
• Confidence: MEDIUM-HIGH that this is the single most dangerous reference; LOW on the exact U.S. claim numbers it maps to, because I do not have the '700's claim text (see § 5).

B-2. L.E. Bergeron et al., "Voice store and forward for the automated office"

• Full citation: WESCON Conference Record, vol. 25, September 1981, pp. 1–8, El Segundo, CA, US.
• Date: published September 1981 — before the 1982-09-29 filing.
• Brief description: voice store-and-forward architecture for office automation, i.e., the store-then-deliver message model that is the core of the '700's summary.
• Claim(s) potentially anticipated: cited X in the same EP report (the retrieved text truncates the passage pin — "page 2, left-hand column, lines 36…"). Potentially § 102 against any independent claim reciting store-and-forward delivery of a recorded audio message.
• Confidence: MEDIUM.

C. Prior art recited in the background of a related European document (EP 0 087 849 B2)

Source: https://patentimages.storage.googleapis.com/0f/3f/e4/82171fd80fface/EP0087849B2.pdf

• Bergland et al., International Switching Symposium, 7th–11th May 1979, pp. 1256–1262 — call-answering service; also proposals for an "advance calling (AC)" service in which a subscriber records a message plus a future delivery time and the system makes periodic delivery attempts, with delivery-status recording. Date: May 1979.
• US 4,160,125 A — telephone polling apparatus that delivers a pre-recorded message to a plurality of telephones in sequence and then records replies. Date: 1979-07-10 (filed 1977-07-18).
  • § 102 relevance: This is the nearest single-reference teaching of the '700's own summary language — "reproduced information is then sequentially transmitted to the selected recipients' telephone station." Potentially § 102 against that specific sequential-delivery limitation; § 103 in combination for the automatic-deletion-after-transmission limitation.
  • Confidence: MEDIUM (the reference is real and dated; the claim mapping is inferred).
• S. Boies, "A Computer Based Audio Communication System," ABCC, New York, January 23–25, 1978, pp. 369–372. Date: Jan. 1978. Computer-based audio messaging; potentially § 102 against generic "electronic digital signal processor + digital memory storing digital representations of audio" claims.
• Note: the EP document itself frames the invention as an improvement over these, on the ground that the prior systems lacked two-way reply capability — which is directly relevant to the '700's reply/redirect special-function-code claims (FIGS. 18–20).
• Confidence: MEDIUM on the references; the parenthetical juxtaposition is the EP examiner's/applicant's framing.

D. Same-family U.S. patents that will surface as apparent "prior art" (handle with care)

US 4,581,486; US 4,585,906; US 4,580,012; US 4,601,291; US 4,602,129; US 4,640,991; US 4,757,525; US 4,761,807 — all Matthews/VMX, all priority 1982-09-29 or 1979-11-26, several granted 1986–88 (i.e., their applications were copending and their grants are after the '700).

• § 102 warning: these share the same applicants and the same priority chain. Under pre-AIA § 102(e) a granted U.S. patent can be art, but same-inventive-entity/common-ownership family members are not proper anticipatory references. Do not treat the "Cited By" tables that list US4652700A alongside them as evidence of prior art.
• Confidence: HIGH on the family relationship.

4. Claim mapping — the honest ceiling on what I can assert

The earlier-generated section already flagged that the '700's claim set is not present in the retrieved text, and that limitation carries straight into this task: I cannot state "reference X anticipates claim N" with the specificity you need without the claim language. What I can map is reference-to-feature:

5. What I could not do, and how to close it

• Not retrieved: the '700's own front-page [56] References Cited (U.S. patents, foreign patents, and non-patent publications actually cited by the U.S. examiner), and the claim text. My search budget was exhausted before I could reach the primary sources below.
• Highest-value verification steps (in order):
  1. USPTO Patent Public Search (https://ppubs.uspto.gov) or Patent Center (https://patentcenter.uspto.gov) — retrieve US 4,652,700 and read the printed front page, items [56] References Cited and Claims.
  2. Espacenet record for US4652700 — the "Cited documents" tab gives the examiner-cited list.
  3. Google Patents "Patent Citations" table on https://patents.google.com/patent/US4652700A/en — present in the page but not captured in the fetched text here.
  4. The counterpart EP file (EP 0 106 575 / EP 0 341 800) for the full EPO search report and any opposition history — the richest examiner reasoning I found on this exact disclosure (URL in § 3.B).
• Confidence summary: patent identity and family relationship — HIGH. That Lincoln 1982 and Bergeron 1981 are the most relevant technical publications — MEDIUM-HIGH. That US 4,160,125 is the best U.S. patent-level reference for the sequential-delivery limitation — MEDIUM. Exact § 102 claim-by-claim anticipation — LOW / not determinable without the claim text, and I will not assert it.

If you can supply the [56] block or the claims, I can produce the reference-by-reference § 102 chart you're asking for with proper claim-level granularity.

I'll ground this in the actual prior-art record for US 4,652,700 before analyzing.

Let me pull the actual cited references and family history.

This is a major find — I now have the actual claim set and the full prior-art section (55 patent citations + 11 NPL references). Let me verify a few of the less-familiar cited references before I build combinations.

I retrieved substantially more than was available to the earlier sections — including a verbatim copy of the '700's own front page and the family's prior-art citation sets. That changes two things materially, and I flag both up front.

§103 Obviousness Analysis — US 4,652,700

0. Threshold issues that must be resolved before the analysis bites

(a) The claim set is still not verified for US4652700 itself, and my searches surfaced a sibling's claim set. I retrieved a 17‑claim set reciting speaker‑independent templates, speaker‑dependent command templates, "control receptive states," state‑based template subgroups, and guided enrollment — but that text is hosted on the US 4,757,525 page (https://patents.searchlight.law/doc/US4757525), not the '700 page. By contrast, the '700's own front page (retrieved verbatim from https://patentimages.storage.googleapis.com/1f/2d/83/67a100873445ea/US4652700.pdf) gives an abstract about "deposit, storage and delivery of audio messages to both user and non‑users with limited access provided to the non‑user under the control of the user… A FAX transmission device (19) is also provided" — i.e. user‑controlled message addressing, not speech recognition.

→ This confirms the earlier "Patent summary" section's low‑confidence inference and contradicts the speech‑recognition claim set as a description of the '700. I therefore analyse both scopes below, clearly separated. Verify the '700's actual claims before relying on either.

(b) Provenance of the "Prior Art section." The fetched '700 record's only explicit prior‑art content is the Google Patents keyword block (user, message, program, input, signal). Its front‑page "References Cited" list did not come through. The reference lists I could retrieve are:

• 51 patent references + 32 NPL items shown for sibling US 4,602,129 (https://portal.unifiedpatents.com/patents/patent/US-4602129-A), and
• 55 patent citations + 11 NPL items shown on the US 4,757,525 sibling page.

These overlap heavily (Kraus '486; Kienzle; Riesz '489; Celentano '880; Friedman '306; Cornell '933/'910; Gates '810; Meri '507; Atalla '091; Matyas '738; Boyd '139; Comella '756; Matthews '095; Hyatt '582; Davis '906; Doyle '144; Watari '359; Toy '418; plus the Bergland/Nacon ICC/ISS 1979 papers, the 1980 ECS brochure, the Jan–Feb 1981 Business Communications Review "Voice Message Exchange" article, and the 1976 Communications News hospital article). Because '129 (App. 06/427,591, filed 1982‑09‑28) and '700 (App. 06/428,243, filed 1982‑09‑29) are same‑day siblings, that shared citation set is a fair proxy for the '700's own face citations — but it is a proxy, not the record.

Literal‑reading flags (no auto‑correction applied): the list I retrieved reads "US3408383 | 1968‑09‑01 | Kienzle et al."; the '129 page separately lists "US‑3403383‑A … Integrated Analog‑digital Switching System with Modular Message Store‑and‑forward Facilities." I am treating these as two distinct entries as written and do not reconcile them. Likewise "US4385359 (1983)" and "US4554418 (1985)" carry publication dates after the '700's 1982‑09‑29 filing date; their §102/§103 eligibility turns entirely on their application filing dates, which I could not verify (search budget exhausted).

1. Critical date — the single most important point

The '700 is a CIP: filed 1982‑09‑29, priority claimed from App. 06/097,240 (1979‑11‑26). The specification itself proves the DTMF/keystroke-era origin of the core flow charts — the '700 text says the user "dials a unique authorization number 604" and "the user dialing the identification code digits 618," whereas the sibling '525 says the user "speaks" the same steps. So:

Consequence: the 1980–1981 references in the prior‑art section are §102(b) art as to CIP‑added matter — including the applicants' own "Voice Message Service," ECS Telecommunications (1980) brochure, the AT&T FCC Petition (Mar. 20, 1981), the ECS reply comments (May 14, 1981), and "The Voice Message Exchange," Business Communications Review, Jan.–Feb. 1981. Those last items also support a separate §102(b) public‑use/on‑sale ground (the Business Week, Jun. 9, 1980 article describes the commercial product), independent of §103.

2. Combination A — if the claims are the message‑system / user‑access scope

Elements (from the '700's own abstract)[?]: centralized DSP‑controlled store‑and‑forward voice system coupled to a PBX or central office; digital memory storing digitized messages; recipient address data; automatic delivery; automatic deletion after delivery; inquiry; prerecorded instructional messages; user‑controlled limited access by selected non‑users (OFF NET); FAX deposit.

Motivation to combine (KSR): (i) Known elements performing known functions — Kraus, Kienzle, the IBM Voice Storage Network and the 1980 ECS brochure all perform the same store‑and‑forward function; aggregating a digital store (Cornell/Glenayre) with a call‑answering front end (Meri) is routine. (ii) Design incentive — the '700's own stated problem (repeated, time‑consuming real‑time calls; no delivery to many recipients from one recording) supplies the motivation, and each reference is in the same field, addressing the same problem. (iii) Known technique applied to a known device ready for improvement — imposing an authorization check (Atalla/Matyas/Boyd) on a message store is the textbook security‑hardening step, and making that check subscriber‑configurable is an administrative design choice, not an inventive one. (iv) Predictable result — no new functional relationship arises; the non‑user simply performs the same deposit/retrieval against a restricted mailbox.

Weak point: the FAX‑store‑and‑forward element is poorly covered by this list; expect to reach outside it (1970s facsimile store‑and‑forward art). I did not verify content beyond the listed titles, so each mapping must be confirmed against the reference text.

3. Combination B — if the asserted claims are the speech‑recognition set

This is where the prior‑art section is simultaneously strongest and weakest. Pirz dominates, and the section contains no speaker‑independent recognition reference at all.

B1 (primary combination): US Re. 32,012 (Pirz, Rabiner, Rosenberg, Wilpon — "Spoken Word Controlled Automatic Dialer") + a store‑and‑forward message reference (Kraus '486 / Kienzle / ECS 1980 / IBM VSN) + optionally Meri '507.

Re. 32,012 (https://patents.google.com/patent/USRE32012E, https://uspto.report/patent/grant/Re32012) discloses, per the retrieved text: speaker‑dependent "acoustic feature templates corresponding to reference utterances previously applied by a user"; a set of command words that change operating modes ("off‑hook," "train," "directory," "stop," "error," "hang up"); a training mode in which the user speaks "each command word and each digit"; state‑dependent template restriction — e.g. "the word recognizer [will] recognize the next occurring utterance as only a repertory word template," "the speech recognizer is set to compare the short utterance to only templates for the short duration command words 'stop' and 'error'"; a voice response circuit providing audio feedback of the recognised word; and LPC feature analysis.

Motivation: Substitution of one known input modality for another to obtain a predictable benefit. Re. 32,012's stated purpose — replacing keypad dialling with spoken words — is the same motivation the '525 sibling's background recites ("a user must engage in translating the control function desired into a numeric code… requires the user to either remember the numeric control code numbers or to refer frequently to a system operations manual"). Substituting it into an existing voice‑message system changes nothing about the message system's function; the modification is "the use of a known technique to improve similar devices in the same way." Pirz's state‑based subsetting directly addresses the known accuracy‑vs‑vocabulary trade‑off, supplying a further reason to adopt it in a multi‑command message system.

Strength: High for a claim set limited to speaker‑dependent command recognition with state‑dependent subsets (i.e., the '525/'807‑style claims 5, 6, 7, 9). Moderate for enrollment/tolerance claims (3, 4, 10, 11, 15, 16). Weak for any claim requiring the speaker‑independent access tier (claims 1, 2, 8, 12, 13, 17).

B2 (filling the speaker‑independent gap): the section offers only Atalla '091 / Matyas '738 / Boyd '139 for access control, none of which the listing suggests is voice‑based. The honest conclusion: to invalidate the speaker‑independent‑template limitations you must go outside this prior‑art section — to the known 1970s isolated‑word and speaker‑independent digit recognisers (e.g. Threshold Technology's VIP‑100 line, Scott Instruments VET, Dialog Systems, Verbex; IBM's "Shoebox" lineage; Rabiner/Sambur‑era speaker‑independent digit work; the 1978 TI Speak & Spell), all of which predate 1982 and establish that both template classes and the idea of selecting a generic vs. user‑specific template were old. I did not verify these against the record here and flag them as leads.

B3 (secondary): Deleting/compressing message content (claims tied to quiet‑time compression/editing) → US 3,789,144 (Doyle) and possibly US 4,385,359 (Watari et al.), subject to the latter's filing‑date problem.

4. Secondary considerations and counter‑arguments to anticipate

• Commercial success / long‑felt need: the Voice Systems & Services v. VMX findings (1992‑11‑05 opinion, https://ipmall.law.unh.edu/.../1992.11.05_VOICE_SYSTEMS_AND_SERVICES_INC_v._VMX_INC.pdf) record VMX + licensees at ~83% of a $973M 1991 market. Nexus is the problem for the patentee: that success is attributed in that record to the '752 voice‑mail patent (and '124/'796 automated attendant), and to a system whose prompt/keystroke interface is the pre‑CIP one. Custome success evidence therefore argues the message system, not the CIP‑added features.
• "Sequential" delivery was already construed against VMX in that same opinion (claim 1/21 of '752), showing that the family's commercially important claims were the messaging claims — reinforcing that the CIP features were ancillary.
• §112 pressure: if the '700's asserted claims are the speech‑recognition set while the '700's own description (as fetched) contains no speech‑recognition disclosure (no voice‑processing board, no template description), the priority claim to 1979 fails and a written‑description attack is available — which also removes the narrower critical date.
• Pre‑AIA posture: the patent is pre‑AIA, so Graham factors framed by KSR apply; means‑plus‑function limitations (§112 ¶6) are construed to the '700's disclosed structure — all of it off‑the‑shelf (Intel 80/30 SBC, 8085, 8155, 8755, STC Model 2700 disks), which makes the hardware limitations trivially obvious.

5. Bottom line

1. Strongest §103 case available from this prior‑art section: Re. 32,012 (Pirz/Bell Labs) + a store‑and‑forward voice‑message reference (Kraus '486 or Kienzle or ECS 1980/IBM VSN) (+ Meri '507, + Boyd/Matyas/Atalla for access control). This disposes of every speaker‑dependent‑command, control‑receptive‑state, template‑subset and enrollment limitation.
2. Weakest link — speaker‑independent templates. Nothing in the section is shown to disclose them; that limitation requires art outside the list, and I have not verified such art here.
3. For the message‑system/user‑access scope (which the '700's own abstract supports), the combination Kraus '486 + Friedman '306 + Cornell '933 + a personal‑verification reference (Atalla '091 or Matyas '738) renders the centralized addressed store‑and‑forward with restricted, user‑controlled access a predictable aggregation; Gates '810 / Cornell '910 cover automatic deletion, and Comella '756 / Matthews '095 cover the answer‑delay feature.
4. Verify before relying on any of it: (i) the '700's actual claim set from USPTO Patent Center; (ii) the '700's own front‑page References Cited list; (iii) the application filing dates of US Re. 32,012, US4385359, and US4554418 — three references whose prior‑art status turns on that alone; and (iv) the §102(b) publication dates for the ECS 1980 and Business Communications Review 1981 items, which are the most under‑used weapons here.