Business-phone terms,defined plainly.
Sixteen terms that come up when researching a business phone system. Each entry is a one-paragraph definition followed by the why-it-matters context. Cross-linked.
- A2P 10DLC
A US carrier registration system for application-to-person SMS — required since February 2025 for any business sending SMS over a 10-digit long code.
- Auto-attendant
The recorded greeting and routing logic a caller hears before reaching a person — "Thanks for calling Acme. Our hours are…"
- Business eSIM
A digital SIM that delivers a complete business phone system — call routing, auto-attendant, voicemail with transcripts, recording, hunt groups, IVR — on the cellular voice network, instead of as a softphone app.
- Departments
A team-phone structure where each functional area (sales, support, billing) has its own number, working hours, and routing rules.
- eSIM
An embedded SIM (eSIM) is a digital SIM card built into a phone — provisioned by software, not by inserting a physical card.
- Hunt group
A business-phone routing rule that directs an inbound call to multiple team members in sequence or simultaneously, until one picks up.
- IVR
Interactive Voice Response — the "press 1 for sales, 2 for support" menu callers navigate before reaching a human.
- LOA (Letter of Authorization)
A signed document authorizing a new carrier to port your phone number from your current carrier on your behalf.
- MMS
Multimedia Messaging Service — the protocol for sending images, video, and group threads over a cellular phone number.
- Native dialer
The phone's built-in Phone app — iPhone "Phone", Android "Phone" — which handles all real cellular calls.
- Number porting
Transferring an existing phone number from one carrier to another — a regulated service in the US under FCC rules.
- RCS
Rich Communication Services — the modern messaging protocol replacing SMS, with read receipts, typing indicators, and richer media.
- Voicemail transcript
A text version of a voicemail message, generated automatically by speech recognition — readable on the lock screen instead of audio-only.
- VoIP
Voice over Internet Protocol — the technology behind softphones, internet calling, and most legacy business phone apps.
- VoLTE
Voice over LTE — the standard for delivering high-definition voice calls over a 4G LTE cellular network.
- Working hours
A business-phone setting that defines when a number rings (during hours) versus routes to voicemail or forwarding (outside hours).