RS422 A balanced serial interface for the transmission of digitaldata in point-to-point connectionsRS485 Serial link according to EIA standard RS485RTC Real-time clockRTU Remote terminal unitSA Substation AutomationSBO Select-before-operateSC Switch or push button to closeSCL Short circuit locationSCS Station control systemSCADA Supervision, control and data acquisitionSCT System configuration tool according to standard IEC61850SDU Service data unitSELV circuit Safety Extra-Low Voltage circuit type according toIEC60255-27SFP Small form-factor pluggable (abbreviation)Optical Ethernet port (explanation)SLM Serial communication module.SMA connector Subminiature version A, A threaded connector withconstant impedance.SMT Signal matrix tool within PCM600SMS Station monitoring systemSNTP Simple network time protocol – is used to synchronizecomputer clocks on local area networks. This reduces therequirement to have accurate hardware clocks in everyembedded system in a network. Each embedded node caninstead synchronize with a remote clock, providing therequired accuracy.SOF Status of faultSPA Strömberg Protection Acquisition (SPA), a serial master/slave protocol for point-to-point and ring communication.SRY Switch for CB ready conditionST Switch or push button to tripStarpoint Neutral point of transformer or generatorSVC Static VAr compensationTC Trip coil1MRK 505 393-UEN B Section 23GlossaryLine differential protection RED650 2.2 IEC 443Application manual
