The I/O Terminal Units TU 731F (with screw-type terminals) and TU 732F (with spring-type terminals) are specifically designed for use with AC 700F/AC 900F/S700 I/O modules that incorporate 115-230 V AC inputs and/or 115-230 V AC relay outputs.
The input/output modules (I/O expansion modules) plug into the I/O Terminal Unit. When properly seated, they are secured with two mechanical locks. All the electrical connections are made through the Terminal Unit, which allows the removal and replacement of the I/O modules without disturbing the wiring at the Terminal Unit.