A-Z Termination

The ability of a VoIP provider to terminate (complete) calls to every country and destination in the world, from "A" to "Z".

ACD (Average Call Duration)

The average length of answered calls. Used to measure network performance and traffic quality.

ASR (Answer Seizure Ratio)

The percentage of attempted calls that are successfully answered. Higher ASR indicates a healthier, more reliable route.

CLI (Caller Line Identification)

A service that transmits a caller's telephone number to the called party's equipment. "CLI Routes" guarantee that the caller ID is preserved and displayed correctly.

Codec

A device or program that compresses data to enable faster transmission and decompresses received data. In VoIP, codecs convert analog voice signals into digital packets (e.g., G.711, G.729, Opus).

DID (Direct Inward Dialing)

A virtual phone number that allows direct routing of calls to a specific extension or device within a business, bypassing a receptionist. DIDs can be local, national, or toll-free.

Jitter

The variation in packet arrival time. High jitter can cause voice packets to arrive out of order, resulting in choppy or scrambled audio.

Latency

The time it takes for a voice data packet to travel from its source to its destination. High latency causes delays (lag) in conversation. VoIP aims for latency under 150ms.

NCLI (Non-CLI)

Routes where the Caller ID is not guaranteed to be displayed (often displayed as "Unknown" or a random number). These routes are cheaper but lower quality than CLI routes.

PBX (Private Branch Exchange)

A private telephone network used within a company or organization. It connects internal telephones to each other and to the public switched telephone network (PSTN).

SIP Trunking

A method of sending voice and other unified communications services over the internet. It replaces traditional telephone lines (PRI/ISDN) and connects a PBX to the PSTN via a broadband connection.

Toll Fraud

Unauthorized use of a telecommunications system by a third party to make long-distance calls, usually to expensive international destinations.

VoIP (Voice over IP)

Technology that delivers voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the internet, rather than via the public switched telephone network (PSTN).

VoIP Glossary