CALL ESTABLISHMENT FOR SIMULTANEOUS ANALOG AND DIGITAL COMMUNICATIONS

摘要

CALL ESTABLISHMENT FOR SIMULTANEOUS ANALOG AND DIGITAL COMMUNICATIONS A modem, capable of simultaneously coupling voice and data signals, connects local digital terminal equipment (DTE) and a local telephone to a communications link. To prevent the local DTE from responding to a communications containing only voice signals, the local DTE is notified of an incoming communication only after detection of calling tone signals on the communications link. Such signals indicate a remote DTE desires to establish a data communications path with the local DTE. This operation advantageously prevents the modem from transmitting an annoying answer tone to a calling party.