M2M Control CX530 Technical Manual V1.00
Professional Automotive and industrial M2M/IoT Gateway
Page 16 of 36
RS232 port
This port can be used as a general-purpose RS232 serial port with no hardware handshake signals.
RJ45 connector overview.
Pin
Name
Description
1
RS232 TXD
Transmit Data from serial port, RS232 compatible
2
RS232 RXD Receive Data for serial port, RS232 compatible
4
GND
Signal Ground
RS485 Port
RS485 is a multi-drop network with a maximum of 32 nodes connected simultaneously to the bus.
The RS485 bus contains an RSA and an RSB signal and a signal ground, which must always be
connected to the common signal ground for all nodes connected to the RS485 bus!
The maximum cable length for the RS485 bus is according to the EIA/TIA-485-A standard (max.
1000m @ <100kbit); this limit is highly influenced by the quality of the cable, signaling rate, noise
etc.
At longer cable lengths, noisy environments, or high communication speeds, it might be necessary
to terminate the transmission line with a 120
1
ohm resistor at each end of the transmission line to
terminate it and avoid signal reflections. If the M2M Control CX530 is used as an endpoint node,
the jumper for the RS485 port can be inserted in order to terminate the RS485 communication lines
with 120Ω. By default, the RS485 communication lines are not terminated with 120 Ω.
Please note:
For best performance, protection, and noise immunity, it is advised to use a shielded
cable to connect the device to the RS485 communications bus.
RJ45 connector overview
Pin
Name
Description
3
RSA
RS485 non-inverting signal for RS485 port
6
RSB
RS485 inverting signal for RS485 port
8
GND
Signal ground
1-Wire bus
The 1-Wire bus is available on the RJ45 communication connector. All 1-Wire communication goes
through a single connection, and all 1-Wire devices connected can retrieve power directly from the
1 Assuming use of a CAT5 twisted pair cable
