GR-303 | Article about GR-303 by The Free Dictionary
Also found in: Dictionary
GR-303(Generic Requirement-303) A Telcordia standard interface to a Class 5 telephone switch from a digital loop carrier (DLC). This is the primary interface to the telco switch from the outside world. In order to connect directly to the PSTN, IP phones and IP telephony gateways must adhere to GR-303. See Class 5 switch and IP telephony.