VoIP sales conversations are full of jargon designed to confuse buyers into thinking the technology is more complex than it is. Here are 50 terms explained in plain English — so you can negotiate from a position of knowledge.
The Essential 15 (Know These Before Any Sales Call)
| Term | What It Actually Means | Why You Should Care |
|---|---|---|
| VoIP | Voice over Internet Protocol — phone calls over the internet | The technology replacing landlines |
| SIP | Session Initiation Protocol — the language phones use to set up calls | Like HTTP for web, SIP is for calls |
| PBX | Private Branch Exchange — the box that routes calls in your office | Old: hardware box. New: cloud software |
| UCaaS | Unified Communications as a Service — phone + video + messaging in one | What you are buying when you buy cloud VoIP |
| DID | Direct Inward Dial — a phone number that rings a specific person | Each employee can have their own number |
| Auto-Attendant | The automated greeting: "Press 1 for sales" | Replaces a human switchboard operator |
| Ring Group | Multiple phones ring simultaneously for one call | Ensures someone always answers |
| IVR | Interactive Voice Response — multi-level auto-attendant | "Press 1, then press 2, then press 3" (keep it simple) |
| SLA | Service Level Agreement — uptime guarantee | Ask for MEASURED uptime, not SLA target |
| MOS | Mean Opinion Score — call quality rating (1-5) | Above 4.0 = good. Below 3.5 = bad |
| QoS | Quality of Service — network traffic prioritisation | Ensures voice gets priority over downloads |
| SRTP | Secure Real-time Transport Protocol — encrypted voice | Your calls are encrypted (non-negotiable) |
| Porting | Moving your phone numbers to a new provider | Takes 5-10 business days in UK |
| Codec | The algorithm that compresses voice audio | Opus is best. G.711 is most compatible |
| Dofollow | A type of backlink that passes SEO value | Not relevant to VoIP, but you might see it in marketing |
Network Terms (10)
| Term | Plain English |
|---|---|
| Jitter | How much your internet connection fluctuates — the #1 VoIP quality killer |
| Latency | Delay between speaking and the other person hearing — under 150ms is fine |
| Packet Loss | Percentage of voice data lost in transit — under 1% is acceptable |
| Bandwidth | How much data your internet can carry — each call needs ~100 Kbps |
| VLAN | Virtual LAN — separate network lane for voice traffic |
| DSCP | Traffic marking — tells routers "this is voice, give it priority" |
| SIP ALG | A router feature that BREAKS VoIP — disable it immediately |
| NAT | Network Address Translation — how your router shares one public IP |
| STUN | Helps phones work behind NAT — your provider handles this |
| SBC | Session Border Controller — security gateway for SIP traffic |
Feature Terms (15)
| Term | Plain English |
|---|---|
| BLF | Busy Lamp Field — lights on your phone showing who is on a call |
| Call Park | Put a call on hold and pick it up from any other phone |
| Call Queue | Callers wait in line with hold music until an agent is free |
| Screen Pop | Caller's CRM record appears automatically when the phone rings |
| Click-to-Dial | Click a number in your CRM/email to start a call |
| Whisper | Supervisor speaks to the agent without the caller hearing |
| Barge | Supervisor joins a live call (all parties can hear) |
| Hot Desking | Log into any phone with your extension — it becomes yours |
| Find Me/Follow Me | Calls ring your desk, then mobile, then voicemail in sequence |
| ACD | Automatic Call Distribution — routes calls to the right agent |
| CDR | Call Detail Record — log of every call (who, when, how long) |
| E.164 | International phone number format (+44 20 1234 5678) |
| DTMF | The tones when you press phone buttons (used for IVR menus) |
| Presence | Status indicator — available, busy, away, do not disturb |
| Softphone | Phone app on your computer or mobile (no physical phone needed) |
Business Terms (10)
| Term | Plain English |
|---|---|
| TCO | Total Cost of Ownership — all costs over 3-5 years, not just monthly |
| BAA | Business Associate Agreement — required for healthcare (HIPAA) |
| DPA | Data Processing Agreement — required under UK GDPR |
| LOA | Letter of Authorisation — permission to port your numbers |
| ETF | Early Termination Fee — penalty for breaking a contract |
| ARPU | Average Revenue Per User — what the provider earns from you |
| Churn | Percentage of customers who leave — high churn = bad service |
| NPS | Net Promoter Score — how likely customers recommend the provider |
| RFP | Request for Proposal — formal document asking providers to bid |
| POC | Proof of Concept — trial deployment before full commitment |
The One Term That Matters Most
POC — Proof of Concept. Before signing anything, insist on a POC. Install the system on temporary numbers. Use it for 2 weeks. If it works, sign. If it does not, walk away.
Any provider that refuses a POC does not trust their own product.
DialPhone offers a 30-day POC at no cost. No credit card. No commitment. Because the product sells itself when you actually use it.
