The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 15, 1987
Filed:
Sep. 25, 1986
Sumio Iwase, Tokyo, JP;
Sony Corporation, Tokyo, JP;
Abstract
A cordless telephone in which communication between a base unit connected to a telephone network and a handset unit is carried out by radio waves, includes a transmitting and receiving system in the base unit and a transmitting and receiving system in the handset and first and second control circuits provided in the base unit system and in the handset, respectively, each include a detecting circuit for detecting whether any signal is present in an initally selected channel at the time communication is to be initiated between the base unit and the handset unit. Such signals being present in the initially selected channel may be caused by interference from other cordless telephone systems in the vicinity. Channel selector apparatus acts to change the base unit and handset from the occupied channel to a vacant channel. Depending on whether it is an incoming call or an outgoing call either the first control circuit of the base unit or the second control circuit of the handset selects the vacant channel in response to an instruction command from the other control circuit.