# Modicon 984 Programmable Controllers

All devices in the 984 Controller family are Modbus or ModbusTCP compatible. The communications parameters may be configured using the appropriate Modsoft programming tool. Please refer to the latest Modicon PLC family of products documentation for details.

The RTU is fully compatible with the default communications parameters for the 984 devices. This makes connection and configuration for this family extremely simple. If changes are desired, be sure the DEF/MEM switch is in the MEM position. If the switch is set to DEF, it will be impossible to change the PLCs network communications parameters.