Card Setup
Sealevel Systems
Dual SIO
Page
4
RTS Enable for RS-485
Headers E3 and E4 select whether the RS-485 driver is enabled by the
UART signal
R
equest
T
o
S
end (RTS) or always enabled. With the jumper
installed, RTS enables the driver. Removing the jumper enables the driver
regardless of RTS. E3 controls Port 2 while E4 controls Port 1. This
jumper should only be installed if you are running the board in a multi-
drop polled environment such as RS-485. For normal point to point
RS-422, such as terminal emulation, remove this jumper. Figure 4 shows
both ports configured for RS-422 operation.
E4
E3
1
2
Figure 4 - Header E3 and E4, RS-485 Enable
