| 摘要 |
PURPOSE:To attain a fully duplex communication between data terminals by using a bidirectional circuit as an analog trunk line when a 4-wire system communication between the data terminals stored in an exchange is executed via a 2-wire analog trunk line. CONSTITUTION:Data terminals DTE1 and DTE2 are connected to exchange networks NW1 and NW2 having the 4-wire exchange function via a 4-wire circuit. A 2-wire analog trunk line is used in two circuits 2W and 3W to have connections between exchanges. Thus the data signal sent to the terminal DTE2 from the DTE1 is supplied to an interface MDIF for MODEM and an MODEM via a trunk LDT1, an analog trunk line 3W and a trunk LDT2 after passing through the MDIF and the MODEM, and sent to the terminal DTE2. While the signal sent from the DTE2 is sent to the terminal DTE1 via an analog trunk line 2W, and other signals are sent to the DTE1 through the same route. |
