A

A2P –  Application to person
ACD – Average call duration
ASR – Answer seisure ratio

B

B2B – Business-to-business

C

CDR- Caller detail records
CLI -Calling line identification
CNAM – Caller ID with Name
CoDec – Coder/Decoder
CPC – Calling Party Control

D

DID – Direct Inward Dialing
DND – Do not disturb
DSP – Digital Signal Processor

E

E1 – 30 concurrent calls

H

HD – High Definition

I

ISP – Internet Service provider
IVR-  Interactive voice response

L

LOA – Letter of authorization

M

MOS -Mean Opinion Score

N

NAT- Network address translation

P

P2P – Person to person
PBX – Private Branch Exchange
PDD – Post Dial Delay
PESQ – Perceptual Evaluation of Speech Quality
PSQM – Perceptual Speech Quality Measure

R

RTT – Round-trip delay time

S

SBC – Session Border Controllers Nonce Number Once
SDP – Session Description Protocol
SIP – Session Initiation Protocol
SMPP – Short Message Peer-to-Peer
SNMP -Simple Network Management Protocol

T

T1 – 24 concurrent calls
TLS -Transport Layer Security

U

UC – Unified Communications

V

VAD – Voice Activity Detection
VAT – Value added Tax
VSC –Voice sampler compressor
VoIP – Voice over IP

W

WebRCT- Web Real-Time Communication