| D/A | Digital-To-Analog |
| DAB | Digital Audio Broadcasting |
| DAC | Digital Access Carrier |
| DAC | Digital to Analog Converter |
| DACS | Digital Access Cross-Connect System |
| DAM | DECT Authentication Module |
| DAMA | Demand Assigned Multiple Access |
| D-AMPS | Digital Advanced Mobile Phone Service |
| DARPA | Defense Advanced Research Projects Agency |
| DAS | Distributed Antenna Systems |
| DAVIC | Digital Audio Video Council |
| dB | Decibel(s) |
| DB | Database |
| DBM | Double Balanced Mixer |
| dBM | Decibel reference to 1 milliwatt |
| DBrn | Decibels above reference noise |
| DBS | Direct Broadcast Satellite |
| DC | Direct Current |
| DCC | Data Communications Channel |
| DCF | Dispersion Compensation Fiber |
| DCF | Discounted Cash Flow |
| DCLEC | Data Competitive Local-Exchange Carrier |
| DCM | Dispersion Compensation Module |
| DCN | Data Communications Network |
| DCO | Digitally Controlled Oscillator |
| DCOM | Distributed Component Object Model |
| DCS | Digital Cross-connected System |
| DCS | Digital Cellular System |
| DCS | Distributed Call Signaling |
| DCS | Distributed Communications System |
| DCT | Discrete Cosine Transform |
| DDC | Digital Down Converter |
| DDI | DDI Corporation. Provider of telecom services in Japan |
| DDN | Defense Data Network |
| DDR | Double Data Rate |
| DDS | Direct Digital Synthesis |
| DDS | Dataphone Digital Service |
| DECT | Digital European Cordless Telecommunication |
| DECT | Digital European Cordless Telephone |
| DEMARC | Demarcation point |
| DEMS | Digital Electronic Messaging Service |
| DEMUX | De Multiplex |
| DES | Data Encryption Standard |
| DFB | Distributed Feedback |
| DFC | Dedicated Fiber/Coax |
| DFCA | Dynamic Frequency and Channel Allocation |
| DFE | Digital Front End |
| DFFS | Design for Six Sigma |
| DFM | Design for Manufacturing |
| DFT | Design for Test |
| DGD | Differentiated Group Delay |
| DGFF | Dynamic Gain Flattening Filter |
| DHCP | Dynamic Host Configuration Protocol |
| DiffServ | Differentiated Services |
| DIN | Digital Information Network |
| DIS | Distributed Interactive Simulation |
| DITF | Disaster Information Task Force |
| DLC | Digital Loop Carrier |
| DLCI | Data-Link Connection Identifier |
| DLE | Digital Loop Electronics |
| DLL | Dynamicall-Linked Library |
| DLR | Design Layout Report |
| DM | Dense Mode |
| DMA | Direct Memory Access |
| DMD | Dispersion Management Device |
| DMI | Design Manufacturability Index |
| DM-PS | Dual-Mode Protocol Stack |
| DMS | Digital Multiplex System |
| DMT | Discrete Multitone |
| DMZ | Demilitarized zone |
| DN | Distinguished Name |
| DNL | Differential Non-Linearity |
| DNS | Domain Naming System |
| DNS | Domain Name Server |
| DoA | Direction of Arrival |
| DOC | Department of Communications |
| DOCSIS | Data Over Cable Service Interface Specifications |
| DOD | Department of Defense |
| DOJ | Department of Justice |
| DOS | Disk Operating System |
| DoS | Denial of Service |
| DOSA | Distributed Open Signaling Architecture |
| DOT | Department Of Transportation |
| DOW | Day Of Week |
| DP | Detection Point |
| DPA | Dynamic Phase Alignment |
| DPC | Destination Point Code |
| DPD | Digital Pre-Distortion |
| Dpd | Dynamic Predistorted |
| DPDCH | Dedicated Physical Data Channel |
| DPE | Distributed Processing Environment |
| DPP | Third Generation Partnership Project |
| DPT | Dial Pulse Terminate |
| DqoS | Dynamic Quality of Service |
| DRAM | Dynamic Random Access Memory |
| DRC | Dynamic Reaction |
| DRIE | Deep Reactive Ion Etching |
| DRIF | Digital Radio Interface |
| DRX | Discontinuous Reception |
| D-Rx | Digital Receiver |
| Ds-[x] | Digital Signal [level x] |
| DSA | Digital Step Attenuator |
| DSAA | DECT Standard Authentication Algorithm |
| DSC | DECT Standard Cipher |
| DSCP | DiffServ Code Point |
| DSF | Dispersion-Shifted Fiber |
| DSI | Detailed Spectrum Investigation |
| DSL | Digital Subscriber Line |
| DSLAM | Digital Subscriber Line Access Multiplexer |
| DSLAS | DSL-ATM Switch |
| DSP | Digital Signal Processor |
| DSP | Digital Service Provider |
| DSRC | Dedicated Short Range Communication |
| DSS | Decision Support System |
| DSS | Digital Satellite System |
| DSSS | Direct Sequence Spread Spectrum |
| DSU | Digital Service Unite |
| DSU | Data Service Unite |
| DT | Drive Test |
| DTH | Direct to Home |
| DTM | Dual Transfer Mode |
| DTMA | Double TMA |
| DTMF | Dual-Tone Multifrequency |
| DTV | Digital Television |
| D-Tx | Digital Transceiver |
| DUC | Digital Up Converter |
| DUT | Device Under Test |
| DVB | Digital Video Broadcast |
| DVB-H | Digital Video Broadcasting Handheld |
| DVB-RCS | Digital Video Broadcasting-Return Channel System |
| DVB-RCST | Digital Video Broadcasting-Return Channel System Terminal |
| DVC | Dynamic Virtual Circuit |
| DVD | Digital Video Disc |
| DVFS | Dynamic Voltage and Frequency Scaling |
| DVMRP | Distance Vector Multicast Routing Protocol |
| DVOD | Digital Video On Demand |
| DVR | Digital Video Recording |
| DVS | Dynamic Voltage Scaling |
| DWDM | Dense Wavelength Division Multiplexing |
| DXC | Digital Cross-Connect |