Glossary
Programmable telephony terms in plain language. Definitions are general: how exactly they apply depends on the country and the provider.
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Common terms
| Term | Definition |
|---|---|
| CPaaS | Communications platform offered as programmable services: numbers, voice, SMS, reachable through an API. |
| API | An interface that lets one piece of software control another through requests. |
| SIP | A standard protocol for setting up, changing and ending calls over an IP network. |
| SIP trunk | A SIP link between a PBX and a carrier that carries several calls. |
| PBX | Private branch exchange: equipment or software that handles an organization’s internal and external calls. |
| DTMF | Tones produced by phone keys, used to move through a menu. |
| IVR | Interactive voice response: a voice menu where the caller picks an option by keypad or voice. |
| CDR | Call detail record: direction, timestamp, duration, status and a technical reference for one call. |
| E.164 | The international number format: a plus sign, the country code, then the number, with no spaces. |
| Local number | A number tied to a geographic area. |
| SMS segment | The unit an SMS is split into. A long message counts as several segments. |
| GSM-7 | An SMS encoding with a limited character set, which allows longer segments. |
| UCS-2 | An encoding that covers more characters, with shorter segments. |
| Webhook | A request a service sends to your server to report an event. |
| Webhook signature | A fingerprint computed with a secret that proves the request really comes from the platform. |
| Idempotency | A property of a request that, replayed with the same key, produces no second effect. |
| Number porting | Moving a number from one carrier to another while keeping that number. |
| Masking | Connecting two people through an intermediate number without revealing their real numbers. |
| Dynamic number insertion | Showing a different number depending on the visit source, to learn where a call came from. |
| Call leg | The link between the platform and one party of a call. |
| Billable duration | The duration your contract uses to count a call. |
| SMS sender ID | The name or number shown as the origin of an SMS, under the country’s rules. |