> ## Documentation Index
> Fetch the complete documentation index at: https://docs.orbit.devotel.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Glossary

> Agentic CCC and Orbit terminology explained

# Glossary

Key terms used throughout the Orbit documentation and the customer-communications industry. Orbit is the Agentic Customer Communications Cloud — one platform spanning 9 aaS pillars (CPaaS, CCaaS, UCaaS, AIaaS, NaaS, CSPaaS, RTC PaaS, CXaaS, CDPaaS).

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## A

**A2P (Application-to-Person)**
Messages sent from a software application to a human recipient. Includes notifications, alerts, OTPs, and marketing messages. Contrasts with P2P (person-to-person) messaging.

**Agent**
An AI-powered assistant in Orbit that handles conversations or executes tasks autonomously. Agents use LLMs, custom tools, and guardrails to interact with end users via messaging or voice channels.

**API Key**
A token used to authenticate requests to the Orbit API. Prefixed with `dv_live_sk_` (live secret), `dv_test_sk_` (test secret), `dv_live_pk_` (live publishable), or `dv_test_pk_` (test publishable).

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## B

**BullMQ**
A Redis-based job queue used by Orbit for background processing, including webhook delivery and campaign execution.

**Burst Limit**
The maximum number of API requests allowed per second, separate from per-minute rate limits.

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## C

**Campaign**
A bulk message send to a defined audience. Campaigns can be scheduled, targeted by contact lists or segments, and tracked for delivery metrics.

**Channel**
A communication medium: SMS, WhatsApp, RCS, Viber, Email, or Voice. Orbit provides a unified API across all channels.

**Contact**
A person in your Orbit contact database, identified by phone number, email, or both. Contacts can have tags, custom attributes, and communication preferences.

**CPaaS (Communications Platform as a Service)**
A cloud-based platform that enables developers to add real-time communication features (messaging, voice, video) to applications via APIs. Contrasts with **UCaaS**, which packages finished internal-communication tools (softphone, SIP trunking, team calling) for a business's own staff rather than API building blocks a developer integrates into their own product — see **UCaaS** below.

**Cursor-Based Pagination**
A pagination method where each response includes an opaque cursor token pointing to the next page of results. More stable and performant than offset-based pagination.

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## D

**DTMF (Dual-Tone Multi-Frequency)**
The signal generated when a phone key is pressed. Used in IVR menus for caller input (e.g., "Press 1 for sales").

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## E

**E.164**
The international phone number format: `+[country code][subscriber number]`. Example: `+14155552671`. Required for all Orbit API phone number fields.

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## F

**Flow**
A visual automation workflow built with Orbit's drag-and-drop flow builder. Flows connect triggers, conditions, and actions to automate communication sequences.

**Fallback Channel**
A backup channel used when the primary channel fails to deliver. For example, falling back from WhatsApp to SMS if the WhatsApp message is undelivered after 5 minutes.

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## G

**Guardrails**
Rules applied to AI agent outputs to ensure compliance, safety, and brand consistency. Enforced inside the agent runtime. Examples: no PII exposure, no profanity, brand voice adherence.

**GSM-7**
The default character encoding for SMS, supporting 128 characters (Latin letters, digits, common punctuation). Messages using only GSM-7 characters fit 160 chars per segment.

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## H

**HMAC-SHA256**
A cryptographic signature algorithm used by Orbit to sign webhook payloads. The signature is sent in the `X-Orbit-Signature` header (or the legacy `X-Devotel-Signature` header for backwards compatibility). See the [Webhook Security guide](/webhooks/security) for verification examples.

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## I

**IVR (Interactive Voice Response)**
An automated phone menu system that routes callers using voice prompts and DTMF key presses. Orbit's IVR API supports AI-powered alternatives via agents.

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## K

**Knowledge Base**
A collection of documents stored in Qdrant (vector database) that an AI agent can search during conversations for RAG (Retrieval-Augmented Generation).

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## L

**LLM (Large Language Model)**
The AI model powering agent conversations. Orbit is Anthropic-only — all LLM requests route through a single partner-vetted Anthropic Claude gateway (`claude-opus-4-7`, `claude-sonnet-4-6`, `claude-haiku-4-5-20251001`, `claude-fable-5`). Tenants do not connect their own model-provider keys. Note that `claude-fable-5` is not directly routable — it is transparently coerced to `claude-opus-4-7` at request time, so any agent pinned to it runs on `claude-opus-4-7`.

**Long Code**
A standard 10-digit phone number (e.g., `+14155552671`), as opposed to short codes. Used for both voice and SMS in the US under 10DLC regulations.

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## M

**MMS (Multimedia Messaging Service)**
An extension of SMS that supports media attachments (images, video, audio). Available on numbers with the `mms` capability.

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## N

**Number Porting**
The process of transferring a phone number from one carrier to another. Orbit supports inbound porting from any carrier, typically completed in 7–14 business days.

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## O

**OTP (One-Time Password)**
A short-lived code sent via SMS, WhatsApp, or voice for identity verification. Managed through Orbit's Verify API.

**Opt-In / Opt-Out**
The process by which a recipient consents to (opt-in) or withdraws from (opt-out) receiving messages. US regulations require explicit opt-in for marketing messages.

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## P

**P2P (Person-to-Person)**
Messages exchanged between two humans, typically from personal phone numbers. Subject to different carrier rules than A2P messaging.

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## R

**RAG (Retrieval-Augmented Generation)**
A pattern where an AI agent retrieves relevant documents from a knowledge base before generating a response, improving accuracy and reducing hallucination.

**RBAC (Role-Based Access Control)**
Orbit's permission system with ten roles. The five primary roles are `owner`, `admin`, `developer`, `viewer`, and `billing`. Four least-privilege seats extend it for contact-center and customer-data work: `agent` (agent console), `supervisor` (queue and call supervision), `analyst` (CDP computed-traits read), and `marketer` (campaign and data-quality). `user` is the base authenticated seat for self-service access. Each role has different API and dashboard permissions.

**RCS (Rich Communication Services)**
A next-generation messaging protocol that enables rich media, read receipts, typing indicators, and interactive elements over the default messaging app.

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## S

**Segment**
A single SMS message unit. Standard SMS (GSM-7) supports 160 characters; longer messages are split into segments of 153 characters each. Each segment is billed separately.

**Short Code**
A 5–6 digit phone number used for high-volume SMS campaigns. Requires carrier approval and offers higher throughput than long codes.

**SIP (Session Initiation Protocol)**
A signaling protocol for establishing, modifying, and terminating voice/video sessions. Orbit supports SIP trunking for carrier connectivity.

**SMS API**
The application-layer interface a developer integrates against to send and receive SMS from code — Orbit's is `POST /api/v1/messages/sms` (see [SMS](/channels/sms)). One call handles routing, concatenation, encoding, and delivery-status webhooks, so the integrator never manages a carrier connection directly. Contrasts with **SMS Gateway** below — an SMS API is the contract a developer codes against, not the wire protocol underneath it.

**SMS Gateway**
The underlying infrastructure — historically an SMPP bind, an on-premises appliance, or a GSM-modem device — that relays SMS traffic between a sender and a carrier's SMSC. "Gateway" describes the wire-protocol connection point; most integrators never touch it directly and instead call an **SMS API** (above), which sits in front of one or more gateways.

**SSE (Server-Sent Events)**
A protocol for streaming data from server to client over HTTP. Used by Orbit's agent chat API when `stream: true` is set.

**STT (Speech-to-Text)**
Converting spoken audio to written text. Orbit uses Deepgram Nova-3 for real-time transcription in voice agents.

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## T

**10DLC (10-Digit Long Code)**
A US carrier registration system for A2P messaging over standard 10-digit phone numbers. Registration requires a brand and campaign. See the [10DLC guide](/guides/10dlc-registration).

**TTS (Text-to-Speech)**
Converting written text to spoken audio. Orbit uses Cartesia Sonic 3.5 (primary) and ElevenLabs Flash v2.5 (fallback) for voice agents.

**Template**
A pre-approved message format for business-initiated conversations on WhatsApp and RCS. Templates can include dynamic variables.

**Tenant**
An organization or account in Orbit. Each tenant has isolated data, API keys, and billing. Internally, data is stored in schema `tenant_{uuid}`.

**Tool**
A function that an AI agent can invoke during a conversation. Examples: looking up an order, checking inventory, scheduling an appointment.

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## U

**UCaaS (Unified Communications as a Service)**
A cloud platform that bundles a business's own internal voice, video, and team-messaging tools — browser softphone, SIP trunking, PBX replacement, find-me/follow-me — into one subscription, configured through a dashboard rather than code. Contrasts with **CPaaS** above: UCaaS is a finished internal-communications product, while CPaaS is a set of APIs a developer wires into their own application. Orbit ships both on the same tenant — its [UCaaS pillar](https://orbit.devotel.io/features/ucaas) sits alongside the core CPaaS messaging, voice, and video APIs documented here.

**Unicode**
An extended character set supporting all global scripts, emoji, and special characters. Unicode SMS segments are limited to 70 characters (67 for multi-part).

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## V

**Verify**
Orbit's identity verification service for sending and checking OTP codes via SMS, WhatsApp, or voice.

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## W

**Webhook**
An HTTP callback that Orbit sends to your server when events occur (e.g., message delivered, call completed). Signed with HMAC-SHA256 for security.