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:
May. 11, 1999
Filed:
Jan. 27, 1997
Paul Roy Kennedy, Mesa, AZ (US);
William Chun-Hung Yip, Scottsdale, AZ (US);
Timothy Gerard Hall, Mesa, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A secure communications system (501) including a local digital terminal (510) coupled to an interworking function (538). The interworking function (538) couples the digital radio network (121) to a PSTN (542, 546, 548) and a remote analog communication terminal (552). The system (501) includes a novel method of establishing an end-to-end communication channel between local digital (510) and remote analog (552) terminals wherein the local digital terminal establishes (510) a direct digital channel (121) between itself (510) and the interworking function (538) and transmits a message describing its signaling capabilities to the interworking function (538). The interworking function (538) then trains its modem with the modem of the remote analog terminal (552) such that signaling capabilities of the local digital terminal (510) and the remote analog terminal (552) are not violated. By moving modem training procedures to the interworking function (538), signal processing delays in the local digital terminal (510) do not adversely affect the success of establishing the end-to-end communication channel.