Shopping for a business phone system means running into a lot of unfamiliar terms. SIP trunking. PBX. Auto attendant. UCaaS. Ring group. Hunt group.
This glossary explains the terms you will actually encounter in plain language. No unnecessary complexity.
Core Terms
VoIP (Voice over Internet Protocol): Phone calls transmitted over the internet instead of traditional copper phone lines.
Hosted VoIP: A VoIP phone system where the infrastructure lives in the cloud, managed by the provider. No on-premise hardware required.
PBX (Private Branch Exchange): A phone system that manages internal and external calls for a business. Can be on-premise hardware or cloud-based.
Cloud PBX: A PBX system hosted in the cloud. Managed by the provider. No server room required.
SIP (Session Initiation Protocol): The technology that enables VoIP calls. SIP trunking uses this protocol to connect an on-premise PBX to internet-based calling.
Features and Functions
Auto Attendant: An automated phone menu that answers and routes calls without a live receptionist. Also called a virtual receptionist or IVR.
IVR (Interactive Voice Response): The broader category of automated phone menu systems. Often used interchangeably with auto attendant.
Ring Group: A set of extensions that all ring simultaneously when called. First to answer takes the call.
Hunt Group: Extensions that ring in sequence. One rings first, then the next if unanswered, and so on.
Extension: An internal number that reaches a specific person or department on a business phone system.
DID (Direct Inward Dialing): A direct phone number that routes to a specific extension without going through the main auto attendant.
Voicemail to Email: A feature that delivers voicemail recordings to a user's email inbox as an audio attachment.
Softphone: A software application that enables calls from a computer or smartphone using VoIP. No physical handset required.
Call Queue: A holding area for incoming calls when all agents are busy. Callers wait in order until someone is available.
Call Recording: Automatic or on-demand recording of phone conversations for documentation, training, or compliance purposes.
Technical Terms
Bandwidth: The amount of data your internet connection can carry. VoIP calls require adequate bandwidth to maintain quality.
QoS (Quality of Service): Network settings that prioritize voice traffic over other internet traffic to maintain call quality.
Uptime SLA: A service level agreement that specifies the guaranteed percentage of time the phone system will be operational. 99.999% means less than six minutes of downtime per year.
E911: Enhanced 911. A requirement that VoIP providers register accurate location information so emergency services can respond to the correct address.
Number Porting: The process of transferring an existing phone number from one carrier to another.
BAA (Business Associate Agreement): A HIPAA-required contract between a healthcare organization and any vendor that handles Protected Health Information.
Service Models
UCaaS (Unified Communications as a Service): A cloud-based platform that combines voice, video, messaging, and collaboration tools in one system.
MSP (Managed Service Provider): A company that manages technology infrastructure, including phone systems and IT, on behalf of a business.
SaaS (Software as a Service): Software delivered over the internet on a subscription basis. Most hosted VoIP is a form of SaaS.