Cable, Network Acronyms, Glossary and Term
D-Subminiature: A common connector type that utilises multiple pins
and a D shaped housing.
D: Delta or data channel, 16 kBit/s in BRI, 64 kBits in PRI, used for
signalling and perhaps some packet data.
D3: Third generation channel blank, 24 channels on one T1
D4: Fourth generation digital bank, up to 48 voice channels on two T1's
or one T1C.
D5: Fifth generation channel bank with ESF.
DA: Destination address, field in frame header, 802.
D/A: Digital to analogue decoding of voice signal
D/A: Drop and Add, similar to drop and insert.
DARPA: Defence ARPA, formerly just ARPA.
DAS: Dual Attach, Access Station, device on a main dual FO rings, 4
DASS: Digital Access Signalling, protocol for ISDN D channel in the
dB: Decibel, 1/10th of a bel; 10 log (x/y) where x/y is a ratio or like
quantities, i.e. power.
dBm: Decibel level referenced to 1mW at 1004 Hz into 600 ohms impedance.
dBm0: Power that would be at zero TLP reference level.
dBrn: Power level relative to noise, dBm + 90
dBrn: dBrn through a C weighted audio filter, matches the ear's response.
DB25: Code for 25 pin connector specific for RS232 interface.
D.C.: Direct current used for some signalling forms
DCC: Data Communications Channel, overhead connection in D bytes for
DCE: Digital circuit termination equipment
DCE: Data Communications equipment
DCS: Digital Cross Connected, DACS
DDCMP: Digital data Communications message protocol.
DDD: Direct distance dialling, refer to PSTN
DDS: Digital data system, network that supports DATAPHONE digital services
DDSD: Delay Dial Start Dial, a start stop protocol for dialling into
a CO switch
DES: Data Encryption Standard, moderately difficult to break
D/I: Drop and Insert a mux function or type
Dielectric: The insulating material that separates the centre conductor
and the shielding.
Digtal Camera cable finder
|Digital Flat Panel connector:
||was used in earlier digital LCD computer monitors.
It was restricted by resolution and has been superseded by DVI. DVI-I graphics
cards can be connected to DFP monitors by an adapter. The image shows a DFP socket.
DIP: Dual In-line Package, for silicon chips and switches
DIS: Draft International Standard, preliminary form of OSI standard
DISC: Disconnect, command frame sent between LLC
entities, layer 2.
DLC: Data Link Connection, one logical bit stream in LAPD, layer 2.
DLC: Digtal Loop Carrier, mux system to gather analogue loops and carry
them to CO.
DLCI: Data Link Connection Identifier, address in a frame, I.122
DLE: Data Link Escape, ESC.
DLL: Data Link Layer, Layer 2 OSI.
DM: Disconnected Mode, LLC frame to reject a connection request, layer
DMC: Differential Manchester Code, pulse pattern that puts transition
at centre of each bit time for clocking, transition at start of period for 0,
DMI: Digitally Multiplexed Interface, AT&T interface for 23 64 Kbits
channel and a 24th for signalling.
Drawing: The mechanical process of making conductors smaller by forcing
|Digital Visual Interface (Digital only) connector:
||is used in LCD computer monitors. A competitor to
DFP, it allows higher resolutions and will connect to digital DVI and DFP graphics
cards (with an adapter.). It is being superseded by DVI-I.
|Digital Visual Interface (Integrated) Connector:
||is the most versatile of connectors for monitors.
A DVI-I connection on a monitor will connect to DVI-I graphics cards and to DVI-D,
DFP and 15 pin VGA analogue cards with suitable adapters. Conversely, you can
connect DVI-D and DFP monitors to DVI-I cards with suitable adapters.