Invalidity dossier
US 5819184
Portable communications and data terminal operating to optimize receipt of both incoming CDPD and AMPS messages
Current assignee: Cirrus Logic Inc
Added 9/23/2026, 6:19:02 PM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 5,819,184
Title: "Portable communications and data terminal operating to optimize receipt of both incoming CDPD and AMPS messages"
Patent number / application: US 5,819,184 A; Application US 08/496,282, filed 1995-06-28.
Priority / dates: Priority date 1995-06-07 (claimed from US 08/487,043). Filing date 1995-06-28. Granted and published 1998-10-06. Anticipated expiration 2015-06-07. Legal status listed as "Expired – Lifetime."
Inventor / assignee: Inventor Russell P. Cashman. Original assignee Pacific Communication Sciences, Inc. (assignment recorded 1995-11-21). Current assignee listed as Cirrus Logic Inc. (merger recorded 2018-03-19).
Purpose: The invention "relates generally to wireless communication devices" and "more particularly … to switching wireless portable subscriber stations between both data and voice modes." The subscriber station is to receive both incoming CDPD (Cellular Digital Packet Data) and AMPS (Advanced Mobile Phone Service) messages.
Plain-language scope (per the supplied excerpt): The background explains that AMPS is the analog cellular voice system (FCC-assigned 800–900 MHz); digital data over AMPS suffers from narrow channel bandwidth, transmission errors, signal loss, fading and dead spots that limit baud rate. CDPD provides non-intrusive, packet-switched data sharing AMPS transmission facilities and AMPS frequencies, using connectionless network services and multiple-access channel sharing. A Mobile Data Base Station (MDBS 1) links the Mobile End System (M-ES 2) to an MD-IS, intermediate systems, and fixed end systems; cell transfer between adjacent cells is done independently of normal AMPS hand-off. Both AMPS and CDPD functions "can be handled by the same hand-set or end system equipment," and the MDBS is "preferably located with the AMPS base station." Classifications include H04W36/00, H04W76/20, H04W68/00, and H04W88/06 (multi-mode terminals).
Source: https://patents.google.com/patent/US5819184/en
Not established by this excerpt: The claims' specific limitations and the described embodiments of the switching/optimization mechanism are not reproduced here; the excerpt omits detailed description text ("consult the source for omitted text"). No information is given on validity, enforceability, or prior-art distinctions beyond cited background.
Generated 10/1/2026, 9:42:51 PM
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Assignment history
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Prior art
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