Omega Vehicle Security OMG-COMM2-EX - Manual (Page 9)

Card Setup
OMG-COMM2-EX Page 5
Set the jumper to ‘S’ if you are using more than one OMG-COMM2-EX in a bus
or you wish to completely remove the pull-down resistor for hardware
compatibility. Setting the adapter in this configuration when it is not
accompanied by a pull-down resistor will prevent the ports from triggering an
interrupt.
E10
E9
N S M
N S M
Figure 6 - Headers E9 and E10, Sharing IRQ’s with another adapter
Headers E3 and E4
Position ‘A’ Determines whether the RS-485 driver is enabled by the UART
signal Request To Send (RTS) or always enabled. With the jumper installed in
position ‘A’, RTS enables the driver. Removing the jumper enables the driver
regardless of RTS. E4 sets Port 1 while E3 sets Port 2. This jumper should only
be set to ‘A’ if you are running the board in a multi-drop polled environment
such as RS-485, and you have software that ‘knows how to talk’ on the RS-485
bus. For normal point-to-point RS-422 (such as terminal emulation), make sure
that a jumper at position ‘A’ is not in place.
Positions ‘B’ & ‘C’ determine whether the board provides a direct ground
connection (as in RS-232 and most RS-422), or a 100 ohm high impedance
ground. The high impedance ground is normally used by RS-485 (and some RS-
422) to avoid ground loop currents with long cables. Position ‘B’ selects the
direct ground and position ‘C’ selects the 100 ohm high impedance ground.
A B C A B C
Figure 7 - Headers E3 and E4 (Factory Default