Glossary · 29 terms · 15 letters
Business communications
glossary.
Plain-English definitions for the acronyms, standards, and jargon you encounter when evaluating a business phone, contact center, or AI communications stack. Each entry explains what the term means, why it matters, and where it shows up in real buying decisions.
If you spend any time procuring or supporting business phone systems, you run into a lot of jargon. Some of it is genuinely useful precision (PSTN, SIP trunking, ACD, RTP). A lot of it is vendor labeling — different vendors use different names for the same capability. This glossary is the canonical reference we point teams to when we want a single shared vocabulary.
Each definition has the same shape: a one-sentence answer at the top, a longer "what it actually means" explanation, why it matters to a buyer, and how it shows up in real procurement decisions. Where two terms are commonly confused (UCaaS vs CCaaS, hosted PBX vs cloud PBX, ACD vs auto attendant, 10DLC vs short code), we say so explicitly inside the definition.
The most-consulted entries on this site are VoIP, UCaaS, CCaaS, SIP trunking, call routing, auto attendant, 10DLC registration, and E911 — those are the ones that come up first in nearly every SMB phone-system buying conversation.
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0-9
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A
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After-Call Work (ACW)
ACW (After-Call Work) is the time an agent spends on post-call tasks like notes, CRM updates, follow-ups. AI reduces ACW by automating wrap-up work.
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Auto Attendant
An auto attendant is an automated phone menu that greets callers and routes them to the right extension or department without a human receptionist.
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Automated Call Distribution (ACD)
ACD (Automated Call Distribution) is a system that routes inbound calls to the most appropriate agent or queue based on skills, availability, and rules.
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Average Handle Time (AHT)
AHT (Average Handle Time) is the total average time an agent spends on a customer interaction including talk, hold, and after-call work. Lower AHT means efficiency.
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C
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Call Barging
Call barging is when a supervisor joins a live call with both the agent and customer able to hear them. Used for urgent escalations and high-risk moments.
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Call Center
A call center is a voice-only customer service operation handling inbound and outbound calls. Contrast with omnichannel contact centers that add digital channels.
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Call Routing
Call routing software automatically directs inbound calls to the right agent or team using skills, time, and intent rules. Types, features, and setup explained.
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Call Whisper
Call whisper lets a supervisor speak to an agent during a live call without the customer hearing. Used for real-time coaching, especially in training scenarios.
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CCaaS (CCaaS)
CCaaS (Contact Center as a Service) is cloud-delivered contact center software for managing voice and digital customer interactions with AI, routing, and analytics.
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CSAT (CSAT)
CSAT (Customer Satisfaction Score) measures how satisfied customers are with an interaction or overall experience. Post-interaction surveys, scale 1-5 typical.
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D
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DID Number (DID)
A DID (Direct Inward Dialing) number is a virtual phone number that routes directly to a specific user or extension, eliminating the need for an operator.
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Do Not Call (DNC) List (DNC)
The Do Not Call (DNC) list is the US National Do Not Call Registry of phone numbers that have opted out of telemarketing calls. Scrub outbound lists or face fines.
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E
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F
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H
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I
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N
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Net Promoter Score (NPS)
NPS (Net Promoter Score) measures customer loyalty by asking how likely they are to recommend you. Industry standard for relationship-level customer sentiment.
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Number Porting (LNP)
Number porting is transferring your phone number from one carrier to another. Free on DialPhone, typical 2-5 business days, zero service interruption.
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O
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P
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PBX (PBX)
A PBX (Private Branch Exchange) is a business phone system that routes calls between internal extensions and the outside world. Traditional vs. modern cloud PBX.
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Predictive Dialer
Predictive dialer definition: outbound call automation that dials multiple numbers and connects answered calls to agents. Maximizes talk time under TCPA rules.
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S
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SIP Trunking (SIP)
SIP trunking delivers voice calls over the internet using Session Initiation Protocol. It connects on-premises PBX or SBC to a VoIP provider for PSTN access.
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Softphone
A softphone is a software application that makes and receives phone calls using your computer, laptop, smartphone, or tablet instead of a physical desk phone.
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STIR/SHAKEN (STIR/SHAKEN)
STIR/SHAKEN is the US framework for authenticating caller ID on VoIP calls to combat spam and spoofing. Required by FCC for carriers. Raises trust scores.
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T
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U
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V
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Voice Broadcasting
Voice broadcasting sends one pre-recorded phone message to many recipients at once. How it works, legitimate uses, and the TCPA rules that govern it.
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VoIP (VoIP)
Non-fixed VoIP numbers are not tied to a physical address, unlike fixed VoIP. Learn the differences, use cases, and how non-fixed VoIP works for business.