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:
Aug. 03, 1993
Filed:
Nov. 20, 1989
Yasuyuki Kozima, Hitachi, JP;
Yasushi Yokosuka, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A modem (modulator-demodulator) apparatus provided with modem circuits having different signal processing standards, which is optimized for a facsimile machine. Switching of modem functions can be accurately performed by concurrently operating modems with required standards selected from modems with different standards incorporated in a modem apparatus and incorporating in a common input/output port means for selectively switching an input/output of each modem and a dedicated signal detection means required for the switching, and further by constituting a facsimile using the this modem apparatus so as to perform the switching control from the facsimile body or automatically. Moreover, the modem signal after switching can be obtained by using a low speed modem as dedicated signal detection means, detecting a flag pattern after having completed an initial sequence consisting of detection of the presence (power) of an input signal, automatic gain control (AGC), carrier reproduction (PLL), timing synchronization, etc. and deciding that a signal for receiving a low speed modem signal has been received on the condition that at least one of the flag pattern has been detected.