Connect Tech COM Express Type 2 Carrier Board - User Manual
Revision 0.03
27
Serial Connector RS485
Function
RS485 Serial
Location
P25
Type
2x10 2mm Header
Pinout
Header
Pin
Signal
DB9 Pin
1
RXD+
1
3
TXD+
2
5
TXD-
3
7
RXD-
4
9
GND
5
11
RXD+
1
13
TXD+
2
15
TXD-
3
17
RXD-
4
19
GND
5
RS485 Control Jumpers
The RS485 Control Jumpers are used for implementing the following RS485 modes of operations:
½ Duplex Multidrop
Full Duplex Multidrop
The UART RTS signal is used along with the J11 jumpers to facilitate these modes.
Function
RS485 ½ Duplex and Multi-drop controls
Location
J11
Type
2x4 2mm Header
Pinout
Header
Pins
Signal
1-2
Port 1 Driver
Multidrop Enable
3-4
Port 1 Receiver ½
Duplex Enable
5-6
Port 2 Driver
Multidrop Enable
7-8
Port 2 Receiver ½
Duplex Enable