Quatech RS-422 - Manual (Page 32)

7.3 XCLK
This is the output clock signal used by the transmitter portion of the UART. It is
generally connected to the UART's own receive clock input (RCLK). This is done by
connecting pins 3 and 6 of the jumper block. If desired, XCLK can be transmitted to
an external source over the AUXOUT line by connecting pins 5 and 6 of the jumper
block. Figure 21 shows how to select the XCLK mode.
Loopback XCLK to RCLK Transmit XCLK on AUXOUT
CTS
AUXIN
XCLK
RTS
AUXOUT
RCLK
1
2
3 6
5
4
CTS
AUXIN
XCLK
RTS
AUXOUT
RCLK
1
2
3 6
5
4
Jumpers J5, J7
Figure 21 --- XCLK selection
7.4 AUXIN/AUXOUT Loopback
The AUXIN signal is an input from the external device, and connecting it to the
AUXOUT signal provides for a loopback mode of operation. In other words,
whatever signal is transmitted by the external device over the AUXIN line will be fed
back to the external device over the AUXOUT line. This mode is accomplished by
connecting pins 2 and 5 of the jumper block. Figure 22 shows how to select this
loopback mode.
Loopback AUXOUT to AUXIN
CTS
AUXIN
XCLK
RTS
AUXOUT
RCLK
1
2
3 6
5
4
Jumpers J5, J7
Figure 22 --- AUXIN/AUXOUT loopback
DSCLP-200/300 User's Manual 27