| DA | Demand Assignment |
| DAA | Data Access Arrangement |
| DA/TDMA | Demand Assigned TDMA |
| DAB | Digital Audio Broadcasting |
| DAC | Demand Assignment Circuit Establishment |
| DAC | Digital to Analogue Converter |
| DAD | Demand Assignment Circuit Disestablishment |
| DAIT | Demand Assigned International Terminal |
| DAMA | Demand Assignment Multiple Access |
| DARPA | Defense Advanced Research Projects Agency |
| DASS | Demand Assignment Signalling System |
| DATE | Duly Authorised Telecommunications Entity |
| DAVIC | Digital Audio Visual Council |
| DAVID | Digital Audio/Video Interactive Decoder |
| dB | Decibel |
| DBF | Digital Beamforming |
| dBi | Decibels with respect to an isotropic antenna |
| dBm | Decibels with respect to 1mW |
| DBR | Data Broadcast Receiver |
| DBS | Direct Broadcasting by Satellite |
| DBTR | Digital Bit Timing Recovery |
| dBW | Decibels with respect to 1W |
| DC | Direct Current |
| D/C | Down Converter |
| DCA | Defense Communications Agency |
| DCE | Data Circuit Terminating Equipment |
| DCE | Data Communications Equipment |
| DCE | Despun Control Electronics |
| DCME | Digital Circuit Multiplication Equipment |
| DCP | Data Collection Platform |
| DCPSK | Differentially Coherent Phase Shift Keying |
| DCRT | Data Collection Receive Terminal |
| DCS | Data Collection System |
| DCS | Direct Couple System |
| DC/TDMA | Demand Controlled TDMA |
| DCU | Display and Control Unit |
| DD/C | Dual Downconverter |
| DDI | Direct Digital Interface |
| DDS | Dataphone Digital Service |
| DDS | Digital Data Service |
| DDS | Digital Data System |
| DDS | Direct Digital Synthesis |
| DDS | Domestic Data Service |
| DEC | Declination |
| DEMOD | Demodulator |
| DEMUX | Demultiplexer |
| DES | Data Encryption Standard |
| DES | Digital Encryption Standard |
| DET | Detector |
| DEV | Deviation |
| DFS | Deutsche Fernmelde Satellit |
| DGPS | Differential GPS |
| DIOS | Digital In Band Open Loop Synchronisation |
| DiSEqC | Digital Satellite Equipment Control |
| DL | Downlink |
| D/L | Downlink |
| DLA | Driver/Limiter Amplifier |
| DLC | Dynamic Load Control |
| DLCI | Data Link Connection Identifier |
| DLL | Downline Loading |
| DM | Delta Modulation |
| DMA | Direct Memory Access |
| D-MAC | Type D Multiplexed Analogue Components |
| D2-MAC | Type D2 Multiplexed Analogue Components |
| DMB | Digital Multimedia Broadcasting |
| DM/PSK | Delta Modulation / Phase Shift Keyed |
| DMUX | Demultiplexer |
| DNI | Digital Non-interpolated Interface |
| DNR | Dynamic Noise Reduction |
| DNS | Domain Name System |
| DoD | Department of Defense |
| DOMSAT | Domestic Satellite System |
| DORSY | Dropout Reduction System |
| DP | Dial Pulse |
| DPA | Destructive Physical Analysis |
| DPCM | Differential Pulse Code Modulation |
| DPSK | Differential Phase Shift Keyed |
| DPU | Data Processing Unit |
| DQPSK | Differential Quadrature Phase Shift Keyed |
| DR | Dynamic Range |
| DRT | Data Recording Terminal |
| DRO | Dielectric Resonator Oscillator |
| DS | Direct Sequence |
| D/S | Data/Speech |
| DSB | Double Sideband |
| DSB-SC-AM | Double Sideband Suppressed Carrier Amplitude Modulation |
| DSB-SC-AM W/QM | Double Sideband Suppressed Carrier Amplitude Modulation with Quadrature Multiplexing |
| DSB-SC-ASK | Double Sideband suppressed carrier Amplitude Shift Keyed |
| DSB-SC-ASK W/QM | Double Sideband suppressed carrier Amplitude Shift Keyed with Quadrature Multiplexing |
| DSF | Dielectric Space Frame |
| DSH | Dual Seizure Handling |
| DSI | Digital Speech Interpolation |
| DSIF | Deep Space Instrumentation Facility |
| DSL | Digital Subscriber Line |
| DSN | Deep Space Network |
| DSNG | Digital Satellite News Gathering |
| DSP | Digital Signal Processor |
| DSP | Digital Signal Processing |
| DSR | Digital Satellite Radio |
| DSRM | DAVIC System Reference Model |
| DSSS | Direct Sequence Spread Spectrum |
| DST | Direct Sounding Transmission |
| DTE | Data Terminating Equipment |
| DTF | Dynamic Traffic Filter |
| DTH | Direct To Home Broadcasting |
| DTI | Data Transfer Interface |
| DTMF | Dual Tone Multi Frequency |
| DUS | Data Utilisation Stations |
| DVB-RCS | Digital Video Broadcast - Return Channel by Satellite |
| DVB | Digital Video Broadcast |
| DVT | Design Verification Test |
| DVB-S | Digital Video Broadcast by Satellite |
| DW | Data Word |
| DX | Duplex |
