Digital Data Service 
Data Distribution Service 
Direct Digital Synthesis 
Dataphone Digital Service 
Digital Data Storage 
Domestic Data Service 
Digital Data System 
Direct Digital Synthesizer 
Digital Data Services 
Deflection Detection System 
Doctor of Dental Science 
Data Description Specifications 
Data Dictionary System 
Data Dissemination System 
Digital Dataphone Service 
DIGITAL DISPLAY SCOPE 
Direct Digital Service 
Direct Digital Synthesizers 
Distributed Data System 
Documentation Distribution System 
Driver's Door Switch 
Dust Detector Subsystem 
Daily Data Set 
Dataphone Digital Services 
Design and Development System 
Design Data Sheet 
Device Descriptions 
Digital Data Systems 
Direct Dialing Service 
Direct Digital Sampling