Input/output extension for the easy-E4 control relay with a rated operating voltage of 24 VDC. This extension provides 4 analog inputs for resistance temperature sensors of the type Pt100, Pt1000 and/or Ni1000. The Pt100, Pt1000 or Ni1000 inputs are suitable for two- and three-wire connections. The connections are made using screw terminals. The connection to the easy-E4 control relay or another easy-E4 extension is made using the easy-E4-CONNECT1 connector plug (item Y7-197225) which is included in the scope of delivery.