The CPUs have two built-in RS-232 communications ports. Both ports are 6-pin RJ12 phone type jacks.

• Port 1 supports the Modbus RTU protocol only and can be used as the programming part. Port 1’s communication parameters are fixed and it is used primarily as the ladder logic programming port. Port 1 can also be used to connect the CPU as a MODBUS RTU protocol slave device.
  
• Port 2 is a general purpose port with user configurable communication parameters. Port 2 can be used as a MODBUS RTU master or slave protocol device, or handle ASCII data ‘In’ or ‘Out’.

Both ports supply 5 VDC, so you can connect our C-more Micro HMI panel without an additional power supply.