Quatech DSC-300, DSC-200 user manual Signal Connections, Full-duplex/Half-duplex Operation

2.2 Signal Connections

The DSC-200/300 provides each of two serial ports with four differential signal pairs: TxD, RxD, AUXOUT, and AUXIN. TxD and RxD are always present at the connector. The AUXOUT and AUXIN signals can be used to support RTS/CTS handshaking, external clocking, or external signal loopback. The factory default configuration, as shown in Figure 2, is a loopback of AUXOUT to AUXIN at the connector, with RTS and CTS looped back on the board. There is an extensive discussion of this topic starting on page 19.

2.3 Full-duplex/Half-duplex Operation

The DTR or RTS modem control output of the UART can be used to enable and disable the transmit drivers. The inverse of these signals can also be used to enable and disable the receivers. These options are selectable per channel. The factory default, as shown in Figure 2, is for both the drivers and receivers of both channels to be continuously enabled. Two spare jumpers are installed in neutral positions. For details, refer to page 22.

The DSC-200/300 is shipped from the factory with each channel configured as shown in Figure 2.

XCLK 6 3 RCLK

AUXOUT 5 2 AUXIN

RTS 4 1 CTS

Loopback RTS to CTS Loopback AUXOUT to AUXIN

Loopback XCLK to RCLK

Jumpers J5, J7

Tx ENABLE		3	Rx ENABLE
Tx	ENABLE5	2	Jumpers J6, J8
			RTS
Tx	ENABLE4	1	DTR

Full Duplex Operation

(spare jumpers supplied)

Figure 2 --- Factory default signal interface settings

Quatech DSC-200/300 User's Manual 10