| 摘要 |
PURPOSE:To constitute versatile control commands excellent in frame synchronism by using an HDLC data frame form as the subscriber line signal system and constituting a line terminator (TA), the cell connection control between the TAs and the control commend in the data transmission via an EPBX (digital electronic private branch of exchange). CONSTITUTION:When the call connection operation from a data terminal equipment 1 is started, a communication control section of a terminal equipment (TA) 3 converts a call into the frame constitution shown in figure, and a call command (STA) is sent from a subscriber line signal interface section 7 to a control section 12 of the exchange EPBX. When the EPBX is receptionable, an affirmative acknowledge command (ACK) to the TA 3. When a dial signal is sent next, the TA sends a KDEFLN command to the EPBX, and when it is received normally by the EPBX, the affirmative acknowledgement command to the TA. The dial signal is sent to the opposite TA via the EPBX as an incoming command ORG. When the opposite TA receives the ORG, an incoming signal is sent to the opposite terminal equipment and when the incoming reception signal is received from the terminal equipment, the STA signal is returned to the EPBX. Thus, a link is established between the caller TA and the called TA and the control command is transmitted and received between the TAs.
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