G

gatekeeper

A device, such as a Cisco router, that keeps track of available WAN bandwidth and permits or denies call attempts based on the available WAN bandwidth.

gateway

A router that converts back and forth between a VoIP network and another type of telephony network (such as a PBX or the PSTN network).

glare

The act of picking up a phone before it rings in an attempt to make a phone call and realizing someone else is on the other end of the line.

grade of service (GoS)

A measurement indicating the acceptable percentage of rejected calls during the busiest hour of the day.

ground start

Lets a phone switch know a phone went off-hook by applying a ground potential to the ring lead.