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:
Jun. 16, 1998
Filed:
Apr. 09, 1997
David G England, Chandler, AZ (US);
Intel Corporation, Santa Clara, CA (US);
Abstract
A circuit for providing an interface between a telephone set and a modem having voice processing capabilities that allows digitization of the voice to occur and provides an improved capability for the detection of a signal indicating a transfer from voice mode to data mode. A typical telephone interface consists of a `2 wire system` on which both the incoming and outgoing signals are carried simultaneously. These two signals need to be separated in order to digitize the outgoing signal. This is done using a hybrid transformer network that attempts to subtract the incoming signal from the outgoing signal. To switch from voice mode to data mode, it is necessary to `listen` for the data tones while a voice call is in progress. These tones are sent by a remote modem as a signal for the local modem to switch into data mode. These tones may be received at a very low level which can prevent the tone detection circuitry from properly functioning. To address this situation, according to the invention, the local outgoing signal is extracted from the received tones by the use of a Data Access Arrangement (DAA) which includes a hybrid transformer. The modem now uses this received signal to detect the tones during a voice conversation.