DIGITAL REGISTER SENDER AND LINE CIRCUIT FOR DATA SWITCH

摘要

DIGITAL REGISTER SENDER AND LINE CIRCUIT FOR DATA SWITCH A switching office for line switching digital data messages includes a digital register sender for accepting inband digital address signals that control the switch and for sending inband digital data dial tone and call progress codes to the subscriber and digital line and trunk circuits for interchanging data between the line and trunk and intraoffice channels. The register sender also sends digital data signals to the line and trunk circuits to control the interchange of data and sends a "not ready" call progress code sequence to the calling subscriber when the called subscriber, although on-hook, is not ready to answer a call.