Glossary
Telecom, in plain English
27 terms you will meet while buying or running a business phone system, defined without the vendor gloss. If a term here has a catch, the entry says what it is.
Every term
- 10DLC The registered route for businesses to send SMS from ordinary ten-digit numbers. Compliance
- A2P messaging Text messages sent by a system rather than typed by a person, such as alerts and reminders. Compliance
- Area code The three digits after the country code that identify a geographic region in North America. Phone numbers
- Auto attendant The recorded menu that answers a call and routes it based on what the caller presses. Phone system
- Call queue Holds callers in line and distributes them to agents as they become free. Phone system
- CDR The per-call record of who called whom, when, for how long and what happened. Phone system
- CNAM The name that appears alongside your number on the recipient’s handset. Phone numbers
- Codec The algorithm that compresses your voice for transmission and reconstructs it at the other end. Call quality
- DID A phone number that rings a specific person or department directly, without going through a receptionist. Phone numbers
- E911 Emergency calling that passes the caller’s location to the dispatcher automatically. Compliance
- Extension A short internal number identifying one user or device inside a phone system. Phone system
- Hosted PBX The phone system itself runs in the provider’s data centre, so there is no hardware on your premises. Core concepts
- IVR A system that collects input from callers and acts on it, beyond simply routing the call. Phone system
- Jitter Variation in packet arrival timing, which causes choppy or robotic audio. Call quality
- Latency The delay between someone speaking and the other person hearing it. Call quality
- LOA The signed document proving you have the right to move a phone number between carriers. Phone numbers
- MOS A one-to-five score summarising how good a call sounded. Call quality
- Number porting Moving an existing phone number from one carrier to another while keeping the number. Phone numbers
- Packet loss Packets that never arrive, heard as gaps, clicks or dropped syllables. Call quality
- PSTN The global interconnected telephone network that any phone number can be reached on. Core concepts
- Ring group A set of extensions that ring together or in sequence so a call reaches whoever is free. Phone system
- SIP trunking Voice service delivered to a phone system you already own, over the internet instead of physical lines. Core concepts
- STIR/SHAKEN A framework that cryptographically signs calls so networks can tell whether the caller ID is genuine. Compliance
- Toll-free number A number the business pays for rather than the caller, on prefixes such as 800 and 833. Phone numbers
- UCaaS Voice, video, messaging and presence sold together as one subscription. Core concepts
- Vanity number A number chosen so its digits spell a word or form a memorable pattern. Phone numbers
- VoIP Carrying phone calls as data over an IP network rather than over a dedicated voice circuit. Core concepts