📖 VoIP glossary

Telco jargon, translated.

Every TLA the industry will throw at you — explained the way your mate down the pub would explain it.

ACMA

Australian Communications and Media Authority — the regulator every legitimate Australian phone carrier answers to. We’re a registered carriage service provider.

Auto-attendant

The automated “press 1 for sales” greeting that answers and routes callers. Same thing as an IVR.

BLF

Busy Lamp Field. The little light on a desk phone next to a colleague’s name that turns red when they’re on a call.

Call queue

A virtual waiting line that holds callers — with hold music and position announcements — until an agent is free.

CLI / CLID

Calling Line Identifier — the number that shows up on someone’s phone when you ring them.

Codec

The maths that compresses your voice for the network. G.722 / Opus = HD; G.711 = standard; G.729 = low-bandwidth.

DECT

Wireless protocol used by cordless desk phones and headsets. Better range than Bluetooth, dedicated voice spectrum.

DID

Direct Inward Dial — a published phone number that rings to a specific destination inside your system.

Direct Routing

Microsoft Teams feature that lets a third-party carrier (like us) provide PSTN calling, instead of buying Microsoft Calling Plans.

E.164

International number format, e.g. +611300250319. The standard format we expect for portability.

Failover

Automatic rerouting of your calls to a backup destination (mobile, another site) the moment your internet or a device drops.

FoIP

Fax over IP — for sending faxes over a SIP connection. Mostly replaced by e-fax now.

HD voice

Wideband audio codec (G.722 / Opus) — sounds noticeably clearer than old PSTN narrowband.

Hunt group

A group of extensions that ring in sequence (or simultaneously) until someone answers.

IVR

Interactive Voice Response — "press 1 for sales, 2 for support". Auto-attendant.

Jitter

Variation in the delay between voice packets. Too much and audio breaks up — a sign your network needs QoS.

Latency

The delay between speaking and being heard. Keep it under about 150ms and a call feels natural.

MOS

Mean Opinion Score — a 1-to-5 rating of call-audio quality. Above 4.0 is considered toll-grade.

NAT

Network Address Translation — how your router shares one public IP. Misconfigured NAT is the classic cause of one-way audio.

NBN

Australia’s National Broadband Network. Your internet pipe — VoIP rides on top of it.

PBX

Private Branch eXchange — the phone system that connects internal handsets to outside lines.

PoE

Power over Ethernet — desk phones powered by the network cable, no separate power brick.

Porting

Moving a phone number from one carrier to another while keeping the number.

PSTN

Public Switched Telephone Network — the "real" phone network, what you call when you dial out.

QoS

Quality of Service — network settings that give voice traffic priority over downloads so calls stay clear.

RTP

Real-time Transport Protocol — the stream that actually carries your voice once SIP has set the call up.

SBC

Session Border Controller — the security gateway between your phone system and the public internet.

SIP

Session Initiation Protocol — the signalling layer that sets up VoIP calls.

SLA

Service Level Agreement — the uptime / response promise we make in writing.

Softphone

A phone app on your computer or mobile — no desk handset required.

SRTP

Secure Real-time Transport Protocol — encrypted voice on the wire.

Trunk

A bunch of phone-call paths between two systems (e.g. between us and your Teams tenant).

Twinning

Making one number ring two devices simultaneously (e.g. desk + mobile).

Voicemail-to-text

Transcribes voicemails and sends them to you as text or email, so you can read a message at a glance.

VoIP

Voice over IP — phone calls carried over an internet connection.

Wallboard

A live dashboard (usually on a TV) showing call queues, wait times and agent status in real time.

Still scratching your head?

If a term here didn’t clear it up, ask a real technician. We talk in plain English — no acronym soup, no sales script.