G
- G.711
- G.722
- G.729
- Gateway
- Gateway Control Protocol (MGCP)
- Gateway Controller
- General Inter-ORB Protocol (GIOP)
- General Packet Radio Service (GPRS)
- Geofencing
- Geographic Number
- Gigabit Ethernet
- Global System for Mobile Communications (GSM)
- Global Title Translation (GTT)
- Grading of Service (GoS)
- Greenfield Deployment
- Greylisting
- Ground Fault Detection
- Ground Loop
- Ground Start
- Group Call
- Group Hunting
- Group Pickup
- Group Ring
- Gruppo Numerazione Ridotta (GNR)
- GSM Gateway
- GUI (Graphical User Interface)
