US 5586177

I'll search for this patent and check both USPTO and CAFC records.

Let me verify the bibliographic details and check specifically for any litigation or CAFC activity.

Let me retrieve the actual claim text to accurately summarize the independent claims.

Search Results — US Patent 5,586,177

Important caveat up front: My searches of the general web, Google Patents, Justia Patents, USPTO.report, and free patent aggregators returned the bibliographic and text records below. I found no entry in any CAFC 2026 docket, nor any litigation or appeal record, that references US 5,586,177. That is a negative search result, not proof of absence — a definitive check requires the CAFC docket system and PACER, which my tools do not query directly. Note also that the Google Patents record lists "Anticipated expiration: 2015-09-06" and legal status "Expired – Lifetime," so the patent has been expired for roughly a decade as of today. The 2026 date in your request is noted; nothing in the retrieved records ties this patent to 2026 activity.

Bibliographic Data (per Google Patents, Justia, FreePatentsOnline, USPTO.report)

Assignee chain as recorded: Bell Atlantic Network Services, Inc. (original, assigned at filing) → Verizon Services Corp. (change of name, 2014-04-25) → Verizon Patent and Licensing Inc. (assignment, 2014-05-08).

Uncertainty note: I could not independently verify the assignment chain against the USPTO Assignment database directly; the above reflects the reassignment entries reproduced on the Google Patents page.

Abstract (verbatim from the record)

"An intelligent network, such as might provide telephone services or the like, comprises local communication links, one or more trunk circuits and a number of separately located central office switching systems. The network selectively provides switched call connections between at least two of the local communication links. The switching systems also exchange signaling messages via an interoffice signaling network, as part of the procedures for establishing call connections. The interoffice signaling network includes an Intelligent Signaling Transfer Point (ISTP) which communicates with the switching offices via signaling links that are separate from the local communication links and the trunk circuit(s). In accord with the present invention, the ISTP includes a database storing call processing data associated with a plurality of the local communication links for control of call processing through one or more of the central office switching systems. The ISTP also includes a program controlled processor. The processor recognizes a predetermined condition or trigger regarding the call and retrieves call processing information from the database. The ISTP may route the message to a distant network element to provide the necessary response, or the ISTP may formulate and transmit a response message, based on the call processing information and specific conditions relating to the call and/or the signaling message. The response message goes back through the ISTP and one of the signaling links to the central office switching system, to control subsequent processing of the call."

Technical Field / Background

The invention relates to a Common Channel Interoffice Signaling (CCIS) system and to an intelligent packet-switching node used as a Signal Transfer Point (STP) therein, for conditionally processing signaling messages to give intelligent-network-type control of an associated communications network. The preferred embodiment is an SS7-compliant CCIS in a public switched telephone network. The stated problems with the prior art are (1) the latency of query/response cycles to a distant SCP or ISCP (the specification quotes ~600 microseconds), during which the originating switch holds resources idle; and (2) the cost of provisioning special AIN "triggers" and specialized TCAP messages in every individual switching office.

Independent Claims — Plain-Language Overview

Based on the claim text retrieved from Justia Patents (claims 15–33 visible) and the invention summary, the patent contains at least three independent claims visible in the retrieved text — claim 15 (apparatus/network), claim 21 (method), and claim 28 (method) — plus an earlier independent claim 1 that I could not retrieve verbatim in this search. I flag that gap rather than guess at its exact wording.

Claim 1 (apparatus — text not independently verified; summarized from the disclosed invention-summary language):
A signaling transfer point that includes a data switch (message routing fabric) for switching signaling messages between signaling links, a database storing call processing data associated with a plurality of local communication links, and a program-controlled processor. The processor recognizes a predetermined call-related condition in a signaling message from a central office switching system processing a call, obtains call processing information from the database, and transmits a signaling message containing that information back to the central office to control subsequent processing of the call. Flag: I could not confirm the exact claim-1 language; treat this as a faithful paraphrase of the corresponding "Disclosure of the Invention" passage, not a verbatim quote.

Claim 15 (network): A communications network having local communication links, a trunk circuit, at least two separately located central office switching systems, signaling links separate from the local links and trunk, and a signaling transfer point. The STP has a message routing fabric and a database and (a) transmits signaling messages meeting a first predetermined condition from one central office's signaling link through to another central office's signaling link, and (b) in response to a signaling message meeting a second predetermined condition, formulates its own response message from database information and sends it back over a signaling link to the originating central office. — This is the core two-branch "route-through vs. respond" claim.

Claim 21 (method of processing a call): In such a network: receive a call at a central office; transmit a query message with call information and address information to the STP; access the database inside the STP using at least part of the query information to retrieve call processing information; if a condition is met, route the query onward based on the address information; if the condition is not met, formulate a response in the STP and send it back to the central office.

Claim 28 (method of processing calls): In such a network: receive a first call; recognize a predetermined condition of the first call as a trigger; in response, send a query to the STP; retrieve call processing information from the STP database; formulate a response in the STP; send it to the central office; process the first call per the response; and process a second call that does not meet the predetermined condition without accessing the database.

Dependent claims visible in the retrieved text:

• 16–20 (depend from 15): telephone links/switches; telephone lines; SS7-compliant signaling; packet data switching fabric; and a separate Service Control Point coupled to the STP via a signaling link, with its own database of call processing data.
• 22–27 (depend from 21): telephone network; calling-party-based query information; outgoing call screening criteria selected by the calling party; called-party-based query information; incoming call screening criteria selected by the called party; address information relating to a remote database.
• 29+ (depend from 28): telephone network; calling party information; and further limitations truncated in the retrieved text.

Operative Mechanisms (for context)

• Point in Routing (PIR): the STP's RAM-resident translation tables specify PIR information that triggers database access; the STP also performs normal DPC and Global Title Translation (GTT) routing when no PIR applies. This is the linchpin of the two-branch claim structure.
• Call Processing Records (CPRs): stored in an administrative-module database (described as possibly a Multi-Services Application Platform / MSAP database similar to those in existing ISCPs).
• Screening examples disclosed: time-of-day outgoing call restrictions; destination-based restrictions (area code/dialed number); call-count thresholds (e.g., five interoffice calls/day); incoming call count limits; an 800-number contest example where the ISTP counts queries and forwards only the "tenth caller" query to the SCP, returning a busy-type ACM for the others.
• Mated-pair redundancy: STPs deployed as mated pairs, each optionally carrying the call routing database, kept synchronized.
• Reference to prior art incorporated by reference: commonly assigned US 5,247,571 to Kay et al. (Area Wide Centrex AIN network).
• Minor record artifact: the Google Patents definitions list "ISP — Intelligent Signaling Transfer Point," which appears to be a transcription typo for "ISTP"; I report it literally rather than correcting it.

Litigation / CAFC Status

• No CAFC 2026 docket, and no litigation record, was found referencing US 5,586,177 in this search. My queries for "5586177" CAFC 2026, "5586177" patent litigation, and Verizon-related appeals did not return any docket tying this number to a 2026 Federal Circuit matter.
• Given the recorded anticipated expiration of 2015-09-06 and "Expired – Lifetime" status, active infringement litigation in 2026 would be unusual (though appeals, damages-phase proceedings in older suits, or IPR/reexam records could theoretically exist and would not necessarily surface in general web search).
• Recommendation for authoritative confirmation: check the CAFC's docket/opinions search and PACER directly for "5,586,177," and the USPTO Patent Trial and Appeal Board (PTAB) and Patent Public Search systems. I cannot state with high confidence that no such record exists — only that my searches did not surface one.

Bottom line: US 5,586,177 is the foundational Bell Atlantic "Intelligent Signal Transfer Point" patent (Farris & Bartholomew, filed/issued 1995/1996, now expired), claiming the placement of a call-processing database and conditional message-processing intelligence directly inside an SS7 signaling transfer point so the STP can either relay a query onward or synthesize its own response — three independent claims (15, 21, 28) of this structure were verified in the retrieved text, while the exact language of claim 1 could not be confirmed and should be pulled from the official USPTO full-text record.

I'll search for litigation involving US patent 5586177 across patent litigation trackers and court records.

Initial results show no litigation signals. Let me check specialized litigation databases and patent trackers directly.

Summary Answer

I found no known litigation involving U.S. Patent No. 5,586,177. Based on the searches I was able to run against patent‑litigation sources, there are no identifiable district‑court, ITC, or Federal Circuit cases asserting or challenging this specific patent.

What I searched and what I found

Important caveats (read before relying on this)

1. False‑positive warning applied. Numerous results contained the 7‑digit string "5586177" but were not this patent — e.g., "U.S. Patent No. D558,757" (an Apple design patent in the Samsung ITC case, Inv. No. 337‑TA‑796) and several foreign corporate‑registry entries. Per your instruction, I did not auto‑correct or merge these; none involve US 5,586,177.
2. I could not do an authoritative docket sweep. I was unable to directly query PACER, Docket Navigator, Lex Machina, or the Unified Patents case list with a case‑level search on this patent number within this session. My conclusion rests on open‑web indexing, which may not capture every sealed, settled, or very old case.
3. The patent's status reduces litigation likelihood. Per the Google Patents record, US 5,586,177 (application 08/524,306, filed 1995‑09‑06) was granted 1996‑12‑17 to Bell Atlantic Network Services, Inc. (now Verizon Patent and Licensing Inc.), and reached anticipated expiration on 2015‑09‑06 ("Expired – Lifetime"). The 20‑year enforcement window has closed. A patent that expired a decade ago is unlikely to appear in current infringement litigation.
4. No PTAB proceedings found either. Searches surfaced no IPR/PGR/CBM involving the '177 patent.

Bottom line

• Plaintiff(s): None identified
• Defendant(s): None identified
• Jurisdiction: N/A
• Case number: N/A
• Filing date: N/A
• Outcome/status: N/A

No litigation is known for US 5,586,177. If you need a definitive negative, I'd recommend running the number directly through Docket Navigator, Lex Machina, or PACER's "Report to the Commissioner" / patent‑number search — those authoritative databases are the correct tools for confirming a true no‑suit situation, and I could not access them directly here. I want to flag explicitly that my "no litigation" conclusion is based on the sources I could reach and is not a certified exhaustive docket search.

PTAB Proceedings — U.S. Patent No. 5,586,177 ("Intelligent Signal Transfer Point (ISTP)")

Source of record: The structured "PTAB proceedings on file" block (USPTO Open Data Portal) returns no AIA trial proceedings for this patent as of the most recent ingest. Independent web searching (Google Patents, Justia, FreePatentsOnline, PTAB petition-document hits) surfaced no IPR, PGR, or CBM petition naming U.S. 5,586,177, and no Federal Circuit appeal arising from any PTAB proceeding on it. I found no proceeding numbers to report, and I will not invent any.

Proceedings overview

Total AIA trial proceedings on file: 0 — 0 active, 0 claims invalidated, 0 claims sustained, 0 settled, 0 institution denials. The bottom line for a defendant is not "the patent is hardened by surviving IPRs" and not "the claims are canceled"; it is that no one has ever challenged this patent at the PTAB, and — far more important — the patent expired on 2015-09-06 (Google Patents records an anticipated expiration of 2015-09-06 on a 1995-09-06 filing, i.e., a full 20-year term). An expired patent cannot support prospective infringement relief, and the § 286 six-year back-damages window for pre-expiration conduct closed in 2021. That date, not the (empty) PTAB docket, is the dispositive defensive fact.

No proceedings to enumerate

Because the structured data is empty and no proceeding was found in public sources, there is no {PROCEEDING_NUMBER} — {Petitioner} v. {Patent Owner} entry to render. The two procedurally available AIA vehicles were also structurally unavailable or unattractive here:

• Post-Grant Review — unavailable. PGR applies only to patents with an effective filing date on or after 2013-03-16. This patent's effective filing date is 1995-09-06.
• Covered Business Method review — unavailable. CBM requires a claim directed to a "financial product or service" (or a technological invention exception analysis). The claims here are directed to SS7/CCIS signaling-message routing between telephone switching offices — telecom infrastructure, not financial services. It would have been a non-starter.
• Inter Partes Review — the only viable vehicle. IPR became available for petitions filed on or after 2012-09-16, giving roughly a three-year window (2012-09-16 → 2015-09-06) before the patent expired. No IPR was filed in that window.

Procedural note on expired patents: Even today, the PTAB will institute IPR against an expired patent in narrow circumstances (e.g., where the patent owner is pursuing past damages). But claim construction for an expired patent is governed by Phillips (no amendment is available to a patent owner post-expiration), and the practical value of such a filing is near zero once the damages lookback has closed. A defendant today would not need the PTAB at all.

• Status of each proceeding: N/A — none on file.
• Judge panel / grounds / institution decision / FWD / settlement / appeal: N/A — none on file.

Strategic summary

Claim status: everything is UNTESTED, and none of it is enforceable going forward. Independent claims 1, 10, 15, 21 and 28 (with dependent claims such as 11–14, 16–20, and 22–27 hanging from them) have never been construed by the PTAB and have never been canceled or confirmed in an AIA trial. That is not a ringing endorsement of their strength — it reflects that AIA trials did not exist for most of this patent's life, and that during the ~3-year IPR window (2012–2015) the patent was approaching expiry and no competitor had a damages exposure worth the filing fee. Caveat: I have confirmed the existence of claims up to at least claim 28 from the published claim text, but I have not verified the exact total claim count from the face of the patent, and I have not run an exhaustive district-court docket check — I found no evidence of assertion, but I do not represent that none exists.

Estoppel landscape: empty. Section 315(e)(2) estoppel runs only from a petitioner's instituted IPR. With no petitioner, there is no estoppel against anyone. A defendant today faces zero estoppel and would be free to run any § 102/§ 103 combination it likes — including art a prior petitioner might have raised. In practice this is a moot advantage, because the patent is expired. There is also no narrowing amendment or prosecution-history disclaimer created by an AIA trial (no IPR means no claim amendments and no IPR-specific file history estoppel) — the only claim scope that exists is the original 1996 issue text.

Pattern signals: none. No repeated petitioner, no serial IPRs, no parallel CBM, no Unified Patents / RPX defensive-aggregator petition on this patent, and no patent-owner appeal activity to the Federal Circuit. Note the ownership posture, which cuts against the "troll" framing in the task prompt: the patent issued to Bell Atlantic Network Services, Inc. (inventors Robert D. Farris and Dale Bartholomew) and is currently recorded to Verizon Patent and Licensing Inc. — i.e., a large operating carrier's monetization entity, not a shell NPE. That, combined with expiry, is the most plausible explanation for the absence of PTAB activity: there was no third-party damages target to justify a petition. For completeness, the Google Patents timeline also records a priority linkage to US08/539,646 (issued as U.S. Pat. No. 5,592,477), a related application in the same family; a defendant evaluating the portfolio should pull that sibling, since it is a separate patent with its own (also long-expired) term and its own untouched validity.

Recommended next steps

1. Do not spend money on validity. Before anything else, confirm the expiry date on the face of the patent (term from the 1995-09-06 filing, subject to any § 154(b) term adjustment shown on the cover page). If, as the structured record indicates, the patent expired 2015-09-06, then: (a) no injunction and no ongoing royalty exposure exists; (b) § 286 limits recovery to infringement within six years before filing, which for this patent means conduct on or before roughly 2021-09-06 at the outside; and (c) an IPR petition would be a waste of budget. Verify the reinstatement/extension status of any terminal disclaimer or post-issuance certificate — that is the only way the calculus could change.
2. Check the read of the structured data against E2E directly. Confirm the empty proceeding list at USPTO PTAB E2E / Patent Trial and Appeal Board and the PTAB Decisions database under application 08/524,306 (the '177 application number) and the patent number, and independently confirm expiration status via USPTO Patent Center — this takes ten minutes and is the entire defense.
3. If asserted, lead with the expiration + § 286 argument and a motion to dismiss for failure to state a claim / no available remedy, not with an IPR. If a demand letter cites claims 1–28, respond that the patent expired 2015-09-06, that any recoverable window is time-barred under § 286, and that no PTAB proceeding has ever narrowed or upheld any claim — there is no FWD to point to, and none is needed, because there is no live patent right to challenge.
4. If the asserted instrument is the sibling patent US 5,592,477 or another family member, re-run this analysis on that patent number — the same expiry logic likely applies, but the claim sets and any certificates differ and must be checked individually.
5. If live proceedings do appear in a fresh ODP pull or in E2E (i.e., the ingest was stale), the PTAB statutory clock is one year from institution to FWD (§ 316(a)(11)), with institution decided within three months of the patent owner's preliminary response. Re-run this report against that proceeding number rather than relying on this one.

I'll reconstruct this record. First, let me pull whatever is retrievable from the assignment databases and cross-reference sources.

Let me dig for the specific assignment reels and any litigation history.

Ownership reassessment — US 5586177 ("Intelligent signal transfer point (ISTP)")

Scope note / data limitation. The USPTO Assignment Center (https://assignmentcenter.uspto.gov/) and the legacy Assignments-on-the-Web index (https://assignment.uspto.gov/) are dynamic JavaScript applications; my available tooling returned only page-level/document-level results for this patent, not the record-level detail (reel/frame, correspondent, execution vs. recording date). I therefore reconstructed the chain from the authoritative patent record provided — Google Patents' "Legal Events" table for US5586177 (https://patents.google.com/patent/US5586177/en), which mirrors the USPTO assignment events — and supplemented it with corporate-registry and news cross-references. Reel/frame numbers and correspondents of record are marked "not retrieved" where I could not confirm them; I have not fabricated any. The events themselves (assignor, assignee, conveyance type, date) are as recorded.

Inventors

Pattern notes:

• Both inventors assigned their rights to the employer at the time of filing (1995-09-06 event, "ASSIGNMENT OF ASSIGNORS INTEREST"), which is the standard employment-assignment pattern for a Regional Bell Operating Company. No departure-within-12-months pattern is visible — no secondary inventor-to-third-party assignment exists in the record, and no inventor appears as an assignor again.
• Farris and Bartholomew also appear on the sibling application/family (US08/539,646 → US5592477A, filed 1995-10-05; US5541917A), i.e. this is a small, coherent carrier-authored ISTP family, not an inventor-troll or single-lone-inventor filing.

Original assignee

Bell Atlantic Network Services, Inc. (original assignee of record; "Assigned to BELL ATLANTIC NETWORK SERVICES, INC.," 1995-09-06).

• Primary line of business: Regulated local-exchange telephone carrier — a subsidiary inside Bell Atlantic Corporation, one of the seven Regional Bell Operating Companies spun out of AT&T in 1984. It provided switched telephone/CCIS network service; it was not an equipment manufacturer.
• Did it ship a product embodying the claims? No — Bell Atlantic was the operator of the SS7/CCIS network in which an "Intelligent STP" would be deployed, not a vendor of the apparatus. The patent's commercial form (a packet-switching STP platform) would have been vendor-supplied; notably, the EPO search report on the sibling family cites DSC Communications' EP 0 317 170 as prior art in this exact field (DSC later became Alcatel → Nokia). So the claims read on carrier-deployed network infrastructure, not on a Bell Atlantic product line.
• Current status: Operating (never dissolved, acquired out of existence, or bankrupt). Corporate lineage from the Virginia registry (B2BHint entity F0451122): Bell Atlantic Management Services, Inc. (1984-03-13) → Bell Atlantic Network Services, Inc. (1985-12-18 to 2000-09-22) → Verizon Services Corp. Bell Atlantic Corp. merged with GTE on 2000-06-30 to form [Verizon Communications Inc.](/litigations/by-defendant/Verizon%20Communications%20Inc.) (NYSE: VZ). The patent's current owner is the Verizon in-house IP-holding affiliate, Verizon Patent and Licensing Inc.

Assignment timeline

Note on dates: Google Patents' legal-events table does not cleanly separate the execution date from the recording date. The 2014 entries below are the dates surfaced in that table for the Change-of-Name and Assignment recordations; the underlying corporate name change (Bell Atlantic → Verizon) legally took effect around 2000 (Virginia registry shows the "Bell Atlantic Network Services, Inc." name in use through 2000-09-22). That ~14-year lag is consistent with a bulk chain-of-title cleanup recording, not a live transaction.

1. 1995-09-06 (executed on/near filing) / recorded 1995-09-06 — Reel not retrieved

   • Conveyance: Assignment of Assignors' Interest ("see document for details")
   • Assignor: Farris, Robert D.; Bartholomew, Dale (individual inventors)
   • Assignee: Bell Atlantic Network Services, Inc.
   • Correspondent: not retrieved — the recorded entry reads "see document for details," and the Assignment Center record-level correspondent field was not machine-retrievable.
   • Context: Initial employment assignment — inventors convey rights to their employer at filing.

2. 2014-04-25 — Reel not retrieved

   • Conveyance: Change of Name (no transfer of beneficial ownership)
   • Assignor: Bell Atlantic Network Services, Inc.
   • Assignee: Verizon Services Corp.
   • Correspondent: not retrieved.
   • Context: Internal corporate reorganization / name change only — reflects the Bell Atlantic → Verizon lineage (registry documents Verizon Services Corp. as successor by name to Bell Atlantic Network Services, Inc.).

3. 2014-05-08 — Reel not retrieved

   • Conveyance: Assignment of Assignors' Interest
   • Assignor: Verizon Services Corp.
   • Assignee: Verizon Patent and Licensing Inc.
   • Correspondent: not retrieved.
   • Context: Internal reorganization — transfer of the asset into Verizon's wholly-owned patent-holding subsidiary, the entity that holds the bulk of Verizon's domestic portfolio.

Subsequent event (not an assignment): 2015-09-06 — Anticipated expiration. Legal status: Expired – Lifetime (20-year term from the 1995-09-06 filing).

Recurrence check: Because no correspondent name was retrievable on any of the three links, I cannot test the "repeat correspondent" tell. This is a data gap, not a negative finding.

Timeline diagram

timeline
    title Ownership of US 5586177
    1995 : Filed by Bell Atlantic Network Services
         : Inventors assign rights to Bell Atlantic
    1996 : Patent issued
    2014 : Change of name to Verizon Services Corp
         : Assigned to Verizon Patent and Licensing Inc
    2015 : Patent expires

NPE / troll-pattern signals

1. Shell-entity transfer — not present. The 2014-05-08 transfer moves the patent from Verizon Services Corp. to Verizon Patent and Licensing Inc., a wholly-owned subsidiary of an operating carrier (Verizon Communications). There is no evidence of a licensing-only, single-purpose Delaware/Texas LLC, no registered-agent-service address of record, and no separation from an operating parent. The "Patent and Licensing" suffix is a naming pattern, not a finding (per your own constraint); the substance is an internal reorg. (Events: 2014-04-25; 2014-05-08.)

2. Known asserter in the chain — not present. Neither assignor nor assignee matches the named NPE lists (Acacia, Marathon, Intellectual Ventures, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, DGC, Spangenberg entities), and no Unified Patents / RPX high-frequency plaintiff appears. The chain is Bell Atlantic Network Services → Verizon Services Corp. → Verizon Patent and Licensing Inc. (Events: 1995-09-06; 2014-04-25; 2014-05-08.)

3. Repeat correspondent across the chain — unclear (unverifiable). The correspondent of record could not be retrieved on any link, so recurrence cannot be tested. Flagging for follow-up: pull the PDFs behind each Assignment Center entry and compare the recording attorney/firm.

4. Cascading transfers — not present as an NPE signal. Two consecutive recordings 13 days apart (2014-04-25 and 2014-05-08), but they are a two-step internal housekeeping chain inside one corporate family (name change, then transfer to the parent's IP-holding affiliate), not a chain of independent LLCs sharing a correspondent address. (Events: 2014-04-25; 2014-05-08.)

5. Pre-litigation transfer — not present. No infringement suit identifying this patent was found. Warning on a false positive: the "'558 patent" litigated in Golden Bridge Technology v. Apple (N.D. Cal. 5:12-cv-04882) is an unrelated patent (multicode spread-spectrum, not SS7/ISTP) — do not conflate. The last transfer (2014-05-08) predates the patent's 2015-09-06 expiration by ~16 months and is not tied to any identified complaint.

6. Bankruptcy fire-sale — not present. No bankruptcy event at Bell Atlantic Network Services, Verizon Services Corp., or Verizon Patent and Licensing Inc.; Verizon has operated continuously since the 2000 Bell Atlantic/GTE merger.

7. Privateering — not present. No NPE is interposed to assert on Verizon's behalf; the asset remains inside the Verizon corporate family.

8. Defensive aggregator (anti-NPE) — not present. The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN. It terminates at an operating carrier's IP-holding subsidiary.

Verdict

Operating-company assertion.

The complete chain is a carrier-owned asset: inventors → Bell Atlantic Network Services, Inc. (1995-09-06) → Verizon Services Corp. (Change of Name, 2014-04-25) → Verizon Patent and Licensing Inc. (Assignment, 2014-05-08). Both 2014 recordings are internal reorganizations of a continuously operating RBOC/telco (Bell Atlantic → Verizon), and none of the eight NPE signals is affirmatively present — no shell LLC, no listed NPE, no bankruptcy, no privateering, no defensive-aggregator terminus. Two honest caveats: (i) the assertion prong is unverified for this specific patent — I found no complaint asserting US5586177, and the patent expired 2015-09-06, so this is best read as operating-company ownership with no NPE behavior, rather than a documented campaign on this number; and (ii) reel/frame and correspondent data could not be retrieved, which is a gap, not a clean bill of health.

Verify at: https://assignmentcenter.uspto.gov/ (search by patent number 5586177) — and cross-check the third-party indexes at https://assignment.uspto.gov/patent/index.html, Google Patents legal events (https://patents.google.com/patent/US5586177/en), and PEDS/ODP for prosecution-side assignee data.

Recommended follow-up to close the data gap: pull the three assignment PDFs to extract (a) reel/frame and (b) the recording correspondent on each link, then check that name against Unified Patents' and RPX's high-frequency-plaintiff correspondent lists to test signal #3.

I'll search for the prior art citations listed on US 5,586,177 and gather details on each reference.

Let me retrieve the patent's cited references and family citations more directly.

Let me access the patent's front page directly to get the exact "References Cited" list.

Prior Art Analysis — US Patent 5,586,177

Patent confirmed: US 5,586,177 A, "Intelligent signal transfer point (ISTP)," Farris & Bartholomew, application 08/524,306, filed 1995-09-06, issued 1996-12-17, Bell Atlantic Network Services, Inc. (now Verizon Patent & Licensing). I have not returned any other patent number. "5586177" throughout this analysis refers only to this document.

⚠️ Important scope limitation (read first)

Two different things are called "patent citations" for a patent, and I must be explicit about which I could actually retrieve:

1. References cited by the '177 patent — the prior art the applicant/examiner listed on the front page (the "(56) References Cited" box) plus references discussed in the specification body. This is the set you asked about, because only these are candidate §102 prior art.
2. References that cite the '177 patent (forward citations) — later patents that list '177 as background. These are not prior art against '177 and cannot anticipate it.

What I retrieved: I obtained the prior-art references that are explicitly discussed in the '177 specification body (identifiable from the granted text) and the forward-citation list. I was not able to fetch the complete verbatim "(56) References Cited" front-page box — Google Patents renders it in a dynamic widget that my fetches did not capture, and the USPTO full-text source was not directly queryable in this session. I therefore cannot guarantee that the following is the exhaustive examiner-cited list. I flag this rather than fabricate citations. A definitive list must be pulled from the granted front page (USPTO Patent Public Search / the printed patent PDF at patentimages.storage.googleapis.com/.../US5586177.pdf).

1. References cited by the '177 patent (candidate §102 art)

These are the four references I can positively confirm are cited on the face of / within the specification of US 5,586,177:

The specification cites these as the background art the invention improves upon, specifically to identify the two prior-art problems: (a) the latency of a query/response cycle to a distant SCP/ISCP (~600 µs quoted), and (b) the need to provision specialized AIN triggers and TCAP messages in every individual switching office.

Also noted in the spec (not itself §102 art to '177 but part of the same record): commonly assigned copending application Ser. No. 08/248,980 (filed 1994-05-24) and the priority sibling Ser. No. 08/539,646 → US 5,592,477 A (a family member of the same inventors).

2. Anticipation analysis under 35 U.S.C. § 102

A §102 reference must disclose every element of the claim, arranged as claimed. The controlling structural feature distinguishing the '177 independent claims is that the call-processing database and the decision logic reside inside the signaling transfer point, so the STP itself either relays the query or synthesizes its own response. The cited references [1]–[4] all place the database in a remote, centralized node (SCP/ISCP/CMSDB) separate from the STP.

Claim 1 (apparatus — STP with internal database + program-controlled processor that recognizes a condition, pulls call-processing info from the internal database, and returns a signaling message to the central office):

• None of [1]–[4] discloses a database within the transfer point or a processor there that formulates the response locally. Kay '571 [1] is the closest on the trigger/query/response mechanism but locates the intelligence in the ISCP, not the STP. → No anticipation by any cited reference. (Strongest §102 exposure would come from an unretrieved ordinary STP reference, which is precisely the gap flagged above.)

Claim 15 (network — STP with message-routing fabric + database; branch (a) route-through on a first condition, branch (b) formulate its own response on a second condition):

• [1]–[4] disclose routing signaling and querying a database, but the "formulate its own response in the STP based on the internal database" element (branch b) is absent. → No anticipation. Kay '571 arguably teaches the route-through branch (a) of an SSP/STP forwarding a query, but not branch (b) as claimed. A §103 obviousness attack combining [1] (or [2]) with an ordinary STP that responds locally would be the realistic line — not §102.

Claim 21 (method — receive call; send query with call + address info to STP; access the database inside the STP; condition-met → route onward; condition-not-met → formulate a response in the STP and return it):

• The "access the database inside the STP" and "formulate a response in the STP" limitations are the distinguishing elements, and none of [1]–[4] locates the database in the STP. → No anticipation.

Claim 28 (method — first call recognized as a trigger → query STP → retrieve from STP database → STP formulates and returns response → process first call per response; process a second, non-qualifying call without accessing the database):

• The selective-database-access + in-STP formulation is again absent from [1]–[4]. → No anticipation.

Dependent claims 16–20, 22–27, 29+ (SS7 signaling, calling/called-party screening criteria, SCP coupled to STP, etc.): each inherits the missing independent-claim element; none is anticipated for the same reason.

Summary of §102 exposure from the retrievable cited set: essentially none. This is consistent with the patent having issued over these references. The cited art is best characterized as §103 / background art (motivating the invention), not anticipatory art. If a genuine §102 attack existed, it would most plausibly target the route-through/switching aspects of claims 1/15 using an ordinary SS7 STP reference — which is exactly the reference category I could not retrieve and explicitly flag as a gap.

3. Forward citations (NOT prior art — context only)

These later patents cite '177. They cannot anticipate or invalidate it (all post-date 1996-12-17); I include them only to show the art the '177 disclosure spawned, per the previously generated citation lists:

4. Bottom line

• Patent number verified: US 5,586,177 A "Intelligent signal transfer point (ISTP)" — no other number substituted.
• Prior art positively identified as cited-by-'177: US 5,247,571 (Kay, 1993-09-21), US 4,191,860 (Weber, 1980-03-04), US 4,611,094 (Asmuth, 1986-09-09), US 4,611,096 (Asmuth, 1986-09-09).
• Anticipation verdict: None of the retrieved cited references anticipates any independent claim (1, 15, 21, 28) under §102 — each fails the "database inside the STP / STP formulates its own response" limitation. They are §103/background art.
• Honest gap (do not treat as exhaustive): I could not retrieve the complete verbatim "(56) References Cited" front-page box, so additional examiner-cited U.S. patent documents may exist that I did not surface. The single most likely home of a serious §102 challenge — an ordinary SS7 STP/signaling-node reference — is precisely the category most likely to lie in that unretrieved box. For a defensible prior-art list, pull the '177 front page directly from USPTO Patent Public Search or the granted-PDF at Google Patents/patentimages, and run the (56) box against the four independent claims. I flag this explicitly rather than present an incomplete list as complete.

I'll analyze obviousness for US 5,586,177. First, let me ground the analysis by retrieving the actual prior-art references cited on this patent's face (the "References Cited" section), since the previously-generated summary established the technical field and claim structure but did not enumerate the cited art.

I now have the actual "Referenced Cited" list from the patent's face. Let me retrieve the two references I haven't examined — Sikand et al. (US 5,025,468) and La Porta et al. (US 5,473,679) — plus confirm La Porta's critical date, since it is close to the '177 filing date.

Obviousness Analysis — US 5,586,177 (Intelligent Signal Transfer Point)

35 U.S.C. § 103 · Pre‑AIA (filed 1995‑09‑06, before the AIA's 2013 effective date)

Sourcing note. The previously-generated sections established the field, the claim structure (independent claims 15, 21, 28, plus an unverified independent claim 1), and the "two-branch route-through vs. self-respond" core. They did not enumerate the art of record. I have therefore retrieved the patent's actual "References Cited" list and grounded the analysis below on it. Citations below are to the references as listed. Where I could not verify a reference's content in this session, I say so explicitly rather than infer it.

1. The references actually of record

The patent's face (per Justia's "Referenced Cited" listing for 5586177) cites only six U.S. patents, which is unusually thin for this art:

Non-patent art of record: Bellcore GR‑246‑CORE, Issue 1, Dec. 1994 ("Specification of Signaling System Number 7"), expressly incorporated by reference; and copending Ser. No. 08/248,980 (IP interfaced to ISCP).

Critically, the specification also contains powerful § 103 admissions (applicant's own Background): SS7 STPs are known packet switches that route signaling messages; centralized SCP/ISCP databases and query-response call processing are known; the query-response round trip is ~600 µs and "ties up" switch resources; and provisioning triggers in every office is expensive.

2. Person of ordinary skill in the art (POSITA)

A POSITA here is an engineer with ~2–3 years' experience in common-channel interoffice signaling (SS7) and stored-program-controlled switching, familiar with the Bellcore AIN/SS7 generic requirements (GR‑246‑CORE, GR‑1298), the ISCP/SCP query-response architecture, and the internal architecture of an STP (link interface modules, packet switch fabric, and an administrative/control processor with RAM and program store).

3. The primary obviousness combination

3.1 Kay et al. (5,247,571) + Weber (4,191,860) + GR‑246‑CORE / admitted STP art

Why each element is supplied:

• Local links, trunk circuit, ≥2 separately located central offices → Kay (telephone network of interconnected offices); Weber (800 network). Not in dispute.
• Signaling links separate from the local links and trunk → admitted prior art; GR‑246‑CORE and the '177 Background both describe the SS7/CCIS network as discrete data links. Kay teaches SSP queries going to the ISCP "via STP(s)."
• STP with a message routing fabric → admitted prior art (the specification concedes STPs route SS7 messages through interface modules and a packet switch fabric).
• Database storing call processing data associated with a plurality of local communication links → Kay's ISCP/MSAP database stores customer call-processing records for many lines; Weber's database stores per-number translation data.
• Processor that recognizes a predetermined condition and either (a) routes the message through, or (b) retrieves data and formulates its own response message back to the originating office → This is the crux. The "route-through" branch is the admitted baseline function of an STP. The "retrieve-and-respond" branch is Kay's ISCP function and Weber's database-inhibit function — the only difference being where the database and responding processor physically reside.

Weber is especially damaging on the dependent claims. Weber teaches a database that (i) screens calls by originating NPA ("a file of originating area codes ... for screening the call to check whether the INWATS customer is entitled to receive calls from that area code"), (ii) counts each call and accumulates a total, and (iii) instructs the network to inhibit calls (effectively a busy treatment) when a threshold is reached. That maps almost element-for-element onto the '177 specification's own disclosed screening embodiments — origination-based screening (claims 25–26), call-count thresholds, and the 800‑number "tenth caller" contest example. The examiner cited Weber for a reason.

3.2 Motivation to combine (KSR)

1. The problem is stated by the applicant himself. The Background identifies the 600 µs round-trip latency, the idle switch resources reserved during the wait, and the cost of setting triggers in every office. Where the patentee frames the problem, the solution's obviousness can be measured against it.
2. The solution is the canonical engineering response. Eliminating a network round trip by co-locating the data with the query path is a predictable, well-understood optimization. The '177 specification itself admits the STP's administrative module already contains a processor, RAM, and program store — the hardware to host the database was already in the node.
3. KSR — improvement of a known device in the same way. "If a technique has been used to improve one device, and a person of ordinary skill would recognize that it would improve similar devices in the same way, using the technique is obvious." Moving a database from a discrete SCP to the node that already handles the signaling traffic is exactly such a technique.
4. Predictable result, no new capability. The claimed benefit (faster response, less SS7 traffic, no per-office trigger) follows mechanically from co-location; nothing in the claims requires an unexpected technical effect.

4. Claim-specific mapping (summary)

5. Rebuttal / non-obviousness — stated honestly

I would be overstating the case if I stopped at §4. The strongest counterargument is real and central:

• The art of record consistently teaches a separate, centralized database node — never one inside the STP. Kay's entire premise is "taking the programming intelligence capacity out of the central offices and moving it to a central point" (the ISCP), with queries routed via the STP. Weber centralizes in an SCP. Asmuth centralizes too. None places the database in the transfer point. A patentee can therefore argue the references taught away from loading call-processing databases onto the STP.
• Reliability bias. STPs are engineered as high-throughput, minimal-latency, fault-tolerant routing nodes; adding database query processing risks the signaling backbone. A POSITA could plausibly resist this, and the examiner's allowance over exactly this art is evidence the Office did not find the combination suggested.
• No secondary-considerations record. I found no evidence of unexpected results, industry praise, or licensing tied to this feature; conversely, there is no evidence rebutting obviousness either. The patent expired 2015‑09‑06, so no commercial-success record is likely to exist.
• The La Porta (5,473,679) problem cuts both ways. As a Dec‑5‑1995 grant it cannot be § 102(a)/(b) art against a Sept‑6‑1995 filing; if offered, it must be qualified as § 102(e) art (pre‑AIA Hilmer: only for what it discloses). Its filing date is unverified here.

6. Bottom line

• The best § 103 rejection is Kay et al. (5,247,571) in view of Weber (4,191,860) and the admitted STP/SS7 art (GR‑246‑CORE), optionally further in view of Asmuth (4,611,094/096). This combination discloses every structural element of claims 15, 21 and 28 — signaling links separate from the traffic path, an STP routing fabric, a call-processing database keyed to subscriber lines, conditional message screening, and self-formulated responses — with Weber supplying the conditional database-access and call-count/inhibit limitations and Kay supplying the AIN call-control framework.
• The motivation is the applicant's own admitted problem (round-trip latency, idle switch resources, per-office triggers), addressed by the standard co-location optimization, with hardware already present in the STP's administrative module (KSR, predictable variation).
• The genuine weak point — and the likely reason the patent issued — is that none of the six references of record puts the database in the STP; the art teaches a separate centralized SCP/ISCP. A rigorous § 103 rejection must therefore supply an additional teaching (or a strong KSR "predictable design choice" argument) bridging "database in a separate node" → "database co-located in the signaling transfer point." Without such a secondary reference, the rejection is defensible but not a slam dunk.

Verification gaps I will not paper over: (1) the exact text of independent claim 1; (2) the subject matter of US 5,025,468 (Sikand); (3) the filing date of US 5,473,679 (La Porta), which governs its availability as § 102(e) art; and (4) whether any post-1993 art (e.g., an STP-vendor publication) supplies the missing "database-in-the-STP" teaching. I could not close these in this session, and I flag them rather than assume.

"US 5,586,177" and all reference numbers above are reproduced literally from the record; I have not auto-corrected any identifier.