Quatech Asynchronous Communications Adapter DSC-200/300 - Manual (Page 29)

8 External Connections
The DSC-200/300 provides four differential communication signals per channel.
The two output signals are Transmit Data (TxD) and Auxiliary Output (AUXOUT). The
two input signals are Receive Data (RxD) and Auxiliary Input (AUXIN). A ground
signal is also provided.
The available input signals for AUXIN are Clear To Send (CTS) and the Receive
Clock (RCLK). The available output signals for AUXOUT are Request To Send (RTS),
the Transmit Clock (XCLK), and the AUXIN signal (for loopback). Either half-duplex or
full-duplex operation can be selected for each communications channel. If half-duplex
operation is selected, one of the UART's signals (either DTR or RTS) is used to enable
the transmitter drivers. The inverse of the transmitter enable can be used to enable the
receiver drivers.
Factory-installed resistors allow for signal line termination in compliance with
the RS-422 and RS-485 standards. The desired termination can be selected or removed
per port by applying a jumper.
Configuration is done using jumpers J1 through J4 for termination selection, and
jumpers J5 through J8 for interface signal routing. Each jumper block provides the
same functions for its particular channel.
J7, J8 J3, J4 Port 2
J5, J6 J1, J2 Port 1
Signal routing Termination Channel
Figure 17 --- Jumper/Channel correspondence
CTS
AUXIN
XCLK
RTS
AUXOUT
RCLK
1
2
3 6
5
4
1
2
3 6
5
4
RTS
DTR
Tx ENABLE
Tx ENABLE
Tx ENABLE Rx ENABLE
Half-duplex
if 3-6 shorted
Jumpers J6, J8
Jumpers J5, J7
Figure 18 --- Pinout of jumpers J5-J8
Quatech DSC-200/300 User's Manual 29