Detail of an SCMT beacon.SCMT was introduced by RFI in 2003 as the successor of the old RS4 system , which had some major drawbacks similar to the Dutch ATB system.SCMT is a semi-ATP system similar to the Belgian TBL-2 and the Dutch ATB-NG system , and is compatible with ETCS-1 through the use of an STM (Specific Transmission Module) which "translates" the SCMT data into ETCS parsable data.