DBS (Direct Broadcast Satellite): US-term for a high-powered satellite capable of offering TV signals from a satellite to the home, for multi channel reception, with a small antenna.(see also DTH)
Dense Wave Division Multiplexing (DWDM): A technology that provides in fibre the equivalent of frequency division multiplexing, in metallic wire. Separate parallel channels are transmitted on a single fiber, with one wavelength for each channel. Current products enable 16 channels of 2.5 GB each for a total of 40 GB per fiber. DWDM can operate over existing single-mode fiber, and therefore reduce upgrade costs.
Digital: Digital describes electronic technology that generates, stores and processes data in terms of bits and bytes. Digital allows the precise storage of information – whether data, voice, music and video – meaning perfect reproduction is possible at high speeds.
DMC (Digital Media Centre): UPC’s broadcasting coordination centre and play-out facility for video services like VOD and NVOD. Eurohits is part of the DMC.
DOCSIS (Data Over Cable Service Interface Specifications) Specification for transmission of data over a cable network that has been approved by the ITU as an international standard. DOCSIS was developed by MCNS, a consortium consisting of CableLabs and a consortium of North American multi-system operators.
Down Conversation see also EuroDOCSIS
Downstream: Term used to describe traffic and paths that go from the headend to the subscriber.
DSL (Digital Subscriber Lines): A technology for bringing high-bandwidth information over ordinary copper telephone lines. xDSL refers to different variations of DSL, such as ADSL (asymmetrical DSL) and HDSL (high bit-rate DSL).
DTH (Direct to Home): DTH is commonly used to describe residential satellite communication.
DTT (Digital Terrestrial Television) The distribution of digital video signals from terrestrial transmitters.
DVB (Digital Video Broadcasting): A set of standards that define digital broadcasting using existing satellite, cable, mobile and terrestrial infrastructures.
DVR (Digital Video Recorder): feature integrated in some set top boxes enabling subscribers to record, fast forward, rewind programming. See also Personal Video Recorder (PVR)
DWDM (Dense Wave Division Multiplexing): A technology which uses lasers to split the light carried by optic fibre cables into 40 separate colour spectra, each capable of carrying as much data as that previously carried by a single white light signal. There is the potential for trillions of bits per second (Tbps) to travel over a single fibre using this technology.