Rosch Computer EMB-M4, User Manual

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22 EMB-M4 User`s Manual
COM1 Serial Ports
COM1, a 9-pin D-Sub male connector, is the onboard COM1 serial
port of the M4. The following table shows its pin assignments.
Pin # Signal Name
1 DCD, Data carrier detect
2 RXD, Receive data
3 TXD, Transmit data
4 DTR, Data terminal ready
5 GND, ground
6 DSR, Data set ready
7 RTS, Request to send
8 CTS, Clear to send
9 +5V,Ring-IN or +12V
COM2 Serial Ports
COM2, a 9-pin D-Sub male connector, is the onboard COM2 serial
port of the M4. The following table shows its pin assignments.
Pin #
RS232 Mode
Signal Name
RS422/RS485 Mode
Signal Name
1 DCD, Data carrier detect TX- (422/485)
2 RXD, Receive data
TX+ (422/485)
3 TXD, Transmit data RX+ (422)
4 DTR, Data terminal ready RX- (422)
5 GND, ground GND
6 DSR, Data set ready
N.C.
7 RTS, Request to send
N.C.
8 CTS, Clear to send N.C.
9 +5V,Ring-IN or +12V N.C.