G.711
Pulse Code Modulation (PCM) of voice frequencies.
G.722
7 kHz audio-coding within 64 kbit/s.
G.723.1
Speech coders: Dual rate speech coder for multimedia communications transmitting at 5.3 and 6.3 kbit/s.
G.728
Coding of speech at 16 kbit/s using low-delay code excited linear prediction.
G.729
Coding of speech at 8 kbit/s using Conjugate Structure Algebraic-Code-Excited Linear-Prediction (CS-ACELP).
G.xxx
ITU G series recommendations - Transmission systems and media, digital systems and networks.
GAP compatible
Means you can add another manufacturer's handset to your existing cordless set up, providing that it's also GAP compatible. When a handset from a different manufacturer or product range is registered to a base station, some of the features may not be available, or may operate differently.
Gatekeeper
An H.323 entity on a network that provides address translation and controls access to the local area network for H.323 terminals, Gateways and MCUs.
Gateway
A device (usually a switch) that translates data formats, signalling protocols and address information to allow communication between two dissimilar networks.
GRE
General Routing Encapsulation. A protocol that allows one network protocol to be transmitted over another network protocol, by encapsulating the packets to be transmitted within GRE packets.
GIF
Graphical Interface Format. A file format that allows photographs and other graphics to be transmitted over the Internet.
GOB
Group Of Blocks. Comprises of k*16 lines of an image. Each GOB is divided into macro-blocks.
GOP
Group Of Pictures. Contains:- I image: reference or intra-frame image- P images: predicted image (from previous P or I image)- B images: between P images, using forward and backward prediction.
GPRS
General Packet Radio Service. Often referred to as the 2.5G mobile telecommunications system.
Graphics accelerator
Card that fits inside your computer. Increases its graphics performance, allowing you to watch more realistic images, live streaming video and the like.
Grey scales (fax)
Better reproduction of non-text images such as drawings and photographs.
GSM
Global System for Mobile communications. The so-called second generation (2G) mobile telecommunication system.
GSTN
General Switched Telephone Network. See PSTN.
GUI
Graphical User Interface. A mechanism for controlling a device that usually involves abstract representation in the form of pictures and icons.
