Digital IO modules are used to connect to the core module to provide digital inputs and outputs to the core module.There are three versions of the I/O modules. They all have the same 28-pin I/O connector on the front (two rows of 14 pins per connector - two suitable 14-pin socket connectors are provided with spring loaded clip contacts for connecting up to 1.5 mm² twisted connecting wires). In addition to the standard version with 14 digital inputs and 14 digital outputs, there are two special versions with 16 digital inputs or 16 digital outputs only.