What Is a Hosted PBX?

An ACD (automatic call distributor) queue answers incoming calls and routes each one to an available agent based on skill or workload. When no agent is free, the call waits in the queue or is routed elsewhere.

An ATA (analog telephone adapter) connects a regular analog phone or fax machine to a VoIP phone service.

In an attended transfer you speak with the person receiving the call before you hand the caller over.

An auto attendant is the part of an interactive voice response (IVR) system that replaces a human operator and directs callers to the right extension or voicemail box.

A blind transfer passes a call to another person without announcing it first. It is also called an unsupervised or cold transfer.

A call group is a phone system feature that rings one or more groups of agents for an incoming call.

Click-to-dial lets you click a contact in Outlook, a web browser or another contact manager. Your desk phone rings, and when you pick up the number is dialed for you.

A codec (coder-decoder) is software that compresses voice or video into a digital stream for transmission and decompresses it on the other end. Common VoIP codecs include G.711, G.722, G.729 and Opus.

A DID (direct inward dialing) number is a phone number that rings directly to a person, department or device on a PBX, without a separate phone line for each number or an operator to transfer the call.

Enhanced 911 (E911) links a caller’s phone number to a physical address and routes the emergency call to the correct public safety answering point (PSAP) for that address.

Find-me/follow-me forwards a call through a list of phone numbers, at the same time or one after another, so a person can be reached at their desk, mobile or home. Unanswered calls go to voicemail.

A handset is the part of a telephone that holds the earpiece and mouthpiece in a single handle.

Interactive voice response (IVR) plays recorded prompts and lets callers choose options with the keypad or their voice.

POTS stands for plain old telephone service: traditional analog phone lines delivered over copper wire.

QoS gives real-time traffic such as voice and video priority over other network traffic like file downloads, so calls stay clear when the network is busy.

A call routing tree is a set of branching rules that decides where a call goes based on who is calling, the number dialed, the time of day and the caller’s IVR choices.

SIP (Session Initiation Protocol) is the IETF standard signaling protocol used to start, manage and end Internet phone calls and other real-time sessions.

A softphone is a phone application on a computer or mobile device that makes and receives calls with a headset or speaker and microphone.