The SOFREL S500 "New Technologies" range comprises 3 products possessing the same software features and the same types of input-output and communication boards. Only the properties and capacities differ from one Remote Terminal Unit to another, between the upgradeable S500, the compact S530 and the simplified S510.

In addition to its integrated input-output boards, a range of expansion modules can be used to expand the capacity of the S550 Remote Terminal Unit and to allow the use of remote inputs-outputs for distributed facilities.