Resources • Telecoms glossary

Telecoms jargon, translated

Every VoIP, Cloud PBX and connectivity term in plain English – so the sales pitch stops sounding cleverer than it is.

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49 terms explained •Plain English, no sales talk •Written for South African businesses

A3 terms

ACD (Automatic Call Distribution)The routing engine that directs incoming calls to the right agent based on rules like availability, skills, or priority. API (Application Programming Interface)The bridge that lets your phone system talk to other software like your CRM, helpdesk, or booking platform. ATA (Analogue Telephone Adapter)A device that connects a traditional analogue phone to a VoIP network, letting you keep old handsets on a modern system.

B3 terms

BandwidthThe amount of data your internet connection can carry at once – and why it matters for VoIP call quality. BroadbandHigh-speed internet access. In South Africa, this means fibre, fixed wireless, or LTE/5G – the foundation every VoIP system runs on. BYOD (Bring Your Own Device)Using personal smartphones and laptops as business phone extensions via a Cloud PBX app.

C4 terms

Call ForwardingRedirecting incoming calls to another number, extension, or device – essential for remote work and load shedding backup. Call RecordingAutomatically recording business calls for training, compliance, or quality assurance – with POPIA considerations. Cloud PBXA business phone system hosted in the cloud, delivered over the internet. The modern replacement for on-premise PBX hardware. CodecThe algorithm that compresses and decompresses voice audio for VoIP transmission. Determines call quality vs bandwidth usage.

D3 terms

DECT (Digital Enhanced Cordless Telecommunications)Cordless phone technology that works with VoIP systems, giving you wireless handsets around the office or warehouse. DID (Direct Inward Dialling)A system that gives individual employees their own direct phone number without needing a separate physical line for each. DTMF (Dual-Tone Multi-Frequency)The tones generated when you press keys on a phone keypad – the technology behind “press 1 for sales.”

E1 term

Extension DiallingInternal short-code dialling between colleagues on the same phone system – like dialling 201 to reach accounts.

F3 terms

Failover RoutingAutomatic call rerouting when your primary connection goes down – critical for load shedding resilience. Fibre InternetInternet delivered via fibre-optic cable. The gold standard for VoIP in South Africa – fast, symmetrical, and low-latency. Fixed WirelessInternet delivered via radio signal to a fixed antenna. The alternative where fibre isn’t available.

G2 terms

GatewayA device that bridges VoIP and traditional phone networks, converting between digital and analogue signals. Geo-RedundancyHosting systems across multiple geographically separated data centres so service survives if one location goes down.

H3 terms

HD VoiceWideband audio that makes VoIP calls sound clearer and more natural than traditional phone lines. Hosted PBXAnother name for Cloud PBX. A business phone system hosted and maintained by a provider, not on your premises. Hunt GroupsA call routing method that rings a group of extensions in sequence or simultaneously until someone answers.

I2 terms

IP (Internet Protocol)The foundational communication standard of the internet. The “IP” in VoIP – the protocol that moves voice data across networks. IVR (Interactive Voice Response)The automated phone menu that greets callers and routes them – “press 1 for sales, 2 for support.”

J1 term

JitterVariation in the arrival time of voice packets. High jitter = choppy, robotic-sounding calls.

K1 term

kbps (Kilobits per Second)A measure of data transfer speed. Each VoIP call uses roughly 100 kbps – useful for calculating bandwidth requirements.

L2 terms

LatencyThe delay (in milliseconds) between speaking and being heard. Below 150ms is acceptable; below 50ms is excellent. LNP (Local Number Portability)The right to keep your phone number when switching providers. Well-established in South Africa.

M2 terms

Mobile VoIPMaking VoIP calls from a smartphone app over Wi-Fi or mobile data – WhatsApp calls are a form of mobile VoIP. Multi-Line VoIP PhonesDesk phones that handle multiple calls or line appearances simultaneously – essential for receptionists and busy teams.

N2 terms

NAT (Network Address Translation)A router function that can interfere with VoIP if not configured correctly. A common cause of one-way audio. Number MaskingDisplaying a different caller ID than the actual originating number – used by sales teams and delivery services.

O2 terms

On-Premise PBXA phone system where the hardware sits in your building. The traditional model, being replaced by Cloud PBX. Outbound Call CentreA call centre focused on making calls – sales, collections, surveys, appointment confirmations.

P3 terms

Packet LossWhen voice data packets fail to arrive. Even 1–2% causes audible gaps. Usually a network problem. PoE (Power over Ethernet)Technology that delivers both data and electrical power through a single network cable – powers IP phones without separate plugs. PSTN (Public Switched Telephone Network)The traditional telephone network using copper lines. Being decommissioned in South Africa as VoIP takes over.

Q1 term

QoS (Quality of Service)Network settings that prioritise voice traffic over data, preventing call quality issues on shared connections.

R2 terms

Remote ExtensionsConnecting devices to your Cloud PBX from any location – home, client site, or abroad – with the same features as in-office. RouterThe device that connects your office network to the internet. Configuration matters for VoIP quality.

S3 terms

SIP (Session Initiation Protocol)The signalling protocol that sets up, manages, and terminates VoIP calls. The standard behind modern business telephony. SIP TrunkingConnecting an on-premise PBX to the phone network via the internet, replacing traditional Telkom lines. SoftphoneA software app that turns your computer or smartphone into a VoIP phone. Included free with most Cloud PBX plans.

T3 terms

TDM (Time-Division Multiplexing)The legacy technology behind traditional phone networks. Being replaced by IP-based packet switching (VoIP). TMS (Telephony Management System)Software for managing your phone system – monitoring usage, configuring extensions, and generating reports. Toll-Free Numbers0800 and 0860 numbers where the business pays for incoming calls. Used to encourage customer contact.

U1 term

UCaaS (Unified Communications as a Service)Cloud PBX plus video, messaging, and collaboration tools in one subscription. The all-in-one communication platform.

V1 term

VoIP (Voice over Internet Protocol)The technology that transmits phone calls over the internet. The foundation of every modern business phone system.

W1 term

WebRTC (Web Real-Time Communication)Browser-based real-time voice and video without installing software. Powers click-to-call buttons and browser-based softphones.

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