Patent US2757632A successfully refreshed from Google Patents.
EP0258739A2
Expired / Lapsed
EP
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Cordless telephone set operated under multi-channel access
Assignee: Fujitsu Ltd
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Filing: 1987-08-19
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Granted: —
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Expires: 2007-08-19
Abstract
Abstract A cordless telephone set (10) is comprised of a base unit (11) and a handset unit (12) connected by a radio frequency (RF) link. The base unit (11) collects channel information indicating that a channel is busy or idle. The channel information is continuously renewed during a stand-by mode, and the last channel information is stored in a channel RAM (31) of the base unit (11). The same uptodate information is also given to a channel RAM (32) in the handset unit (12) during the same mode. Thus, when the stand-by mode is released, both units can quickly search and find an idle channel common to the two, with reference to the uptodate channel information stored in the respective channel RAM's (31, 32).
Inventors
- 👤 Akio Nakanishi
- 👤 Ken-Ichi Ikegaya
- 👤 Takao Naitoh
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 20:49
CPC Classifications
H; H04; H04M; H04M1/00; H04M1/72; H04M1/725; H04M1/73; H04M1/72502; H04M1/72505; H04M1/72511
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
104 words
A cordless telephone set (10) operated under multi-channel access, comprising a base unit (11) and a handset unit (12) between which a radio frequency (RF) link is formed through a channel selected from previously alloted channels, wherein, the base unit (11) and the handset unit (12) are each provided with a channel random access memory (RAM) (31, 32) for storing uptodate channel information indicating whether a channel is busy or idle, which channel information is continuously renewed and the same channel information is written to both channel RAM's (31, 32) during a stand-by mode and utilized for a quick establishment of the RF link.
Claim 2
Dependent Claim
104 words
A cordless telephone set (10) operated under multi-channel access, comprising a base unit (11) and a handset unit (12) between which a radio frequency (RF) link is formed through a channel selected from previously alloted channels, wherein, the base unit (11) and the handset unit (12) are each provided with a channel random access memory (RAM) (31, 32) for storing uptodate channel information indicating whether a channel is busy or idle, which channel information is continuously renewed and the same channel information is written to both channel RAM's (31, 32) during a stand-by mode and utilized for a quick establishment of the RF link.
Claim 3
Dependent Claim
33 words
A cordless telephone set (10) according to claim 1, wherein the uptodate channel information is continually searched by the base unit (11) and supplied to the handset unit (12) during the stand-by mode.
Claim 4
Dependent Claim
89 words
A cordless telephone set (10) according to claim 2, wherein the uptodate channel information is periodically supplied from the base unit (11) to the handset (12) unit via a first write contact (33-1) at the base unit side and a second write contact (33-2) at the handset unit side, these first and second write contacts (33-1, 33-2) being automatically connected with each other during the stand-by mode when the handset unit (12) is placed on the base unit (11) to allow a battery charge to the handset unit (12).
Claim 5
Dependent Claim
34 words
A cordless telephone set (10) according to claim 3, wherein the uptodate channel information is supplied from the base unit (11) to the handset unit (12) in the form of a serial data transmission.
Claim 6
Dependent Claim
21 words
A cordless telephone set (10) according to claim 4, wherein the serial data transmission is performed by a start-stop transmission method.
Claim 7
Dependent Claim
86 words
A cordless telephone set (10) according to claim 2, wherein the base unit (11) is mainly comprised of a first RF·transmitter and receiver (23) and a first controller (22) mainly comprising a first central processing unit (CPU), while the handset unit (12) is mainly comprised of a second RF·transmitter and receiver (27) and a second controller (26) mainly comprising a second CPU, the first and second CPU's containing said channel RAM's (31, 32) as a first channel RAM (31) and a second channel RAM (32), respectively.
Claim 8
Dependent Claim
82 words
A cordless telephone set (10) according to claim 6, wherein the uptodate channel information is collected by the first RF·transmitter and receiver (23) in cooperation with an electric field detecting means at frequencies corresponding to each channel, the detecting means providing a logic "1" to indicate the channel is busy and a logic "0" to indicate the channel is idle, and the thus detected logic is stored, at respective addresses in terms of the channel numbers, in the first channel RAM (31).
Claim 9
Dependent Claim
20 words
A cordless telephone set (10) according to claim 7, wherein the electric field detecting means comprises a noise squelch (NSQ).
Claim 10
Dependent Claim
42 words
A cordless telephone set (10) according to claim 7, wherein the uptodate channel information is supplied, during the stand-by mode, to the second channel RAM (32) in the second CPU in the form of digital data output directly from the first CPU.
Claim 11
Dependent Claim
52 words
A cordless telephone set (10) according to claim 7, wherein the uptodate channel information is supplied from the first channel RAM (31) in the first CPU via a first modulator-demodulator (MODEM) to a second MODEM in form of analog signal and input to the second channel RAM (32) in the second CPU.
Claim 12
Dependent Claim
46 words
A cordless telephone set (10) according to claim 2, wherein the continuous search for uptodate channel information is stopped every time the handset unit (12) is separated from the base unit (11), and accordingly, the stand-by mode is released to create an RF link establishing mode.
Claim 13
Dependent Claim
72 words
A cordless telephone set (10) according to claim 11, wherein the base unit (11) and the handset unit (12) starts the search for and finding of a channel common to the two units, soon after the stand-by mode, with reference to the last uptodate channel information stored in the first and second channel RAM's (31, 32) respectively, wherein only the channels having logic "0", which indicates an idle channel, are selectively accessed.
References Cited (Backward Citations)
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