Supplemental Type Certificates 
Supplemental Type Certificate 
Sensitivity Time Control 
Sensitivity-Time Control 
Satellite Test Center 
Supplemental Type Certification 
Scientific and Technical Committee 
Society for Technical Communication 
Sound Transmission Class 
Standard Transmission Code 
SHAPE Technical Center 
Spacecraft Test Conductor 
Science and Technology Corporation 
Secure Transaction Channel 
Serving Test Center 
short time constant 
Society of Telecommunications Consulta… 
Software Technology Center 
Space Technology Center 
Space Time Coding 
Switching Technical Center 
System Test Complex 
System Test Controller 
System Time Clock 
Saudi Telecoms Company 
Science and Technology Center 
Science and Technology Centers 
Secondary Tax on Companies 
secondary traffic channel 
Securities Training Corporation