Abbreviations
DC
direct current
DCE
data communications equipment
DCIU
data communications interface unit
DCP
digital communications protocol
DCS
distributed communications system
DID
direct inward dialing
DIP
data interface process
DMA
direct memory access
DNIS
dialed number identification service
DSP
digital signal processor
DSR
data set ready
DSU
data service unit
DTE
data terminal equipment
DTMF
dual tone multifrequency
DTR
data terminal ready
E
EIA
Electronic Industries Association
ESD
electrostatic discharge
ESS
electronic switching system
F
F key
function key
FIFO
FOOS
facility out of service
G
GBCS
Global Business Communications Systems
GOS
grade of service
H
Hz
hertz
I
I/O
input/output
IDI
isolating data interface
IMAPI
Intuity messaging application programming interface
INADS
initialization and administration system
IRQ
interrupt request
ISDN
integrated services digital network
IVC6
integrated voice CELP card (6 channels)
IVR
integrated voice response
