> For the complete documentation index, see [llms.txt](https://wiki.inels.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://wiki.inels.com/inels-home/inels-wireless/transmitters-receivers-and-gateways.md).

# Transmitters, receivers and gateways

The three kinds of device in iNELS Wireless, how they talk to each other, and when to pair directly or use a gateway.

*Part 1 — Understand the system. Read this before anything else.*

An iNELS Wireless installation is made of **three kinds of device**. Once you know which kind each product is, everything else in this manual follows.

***

## The three kinds of device

<table data-view="cards"><thead><tr><th></th><th></th><th></th></tr></thead><tbody><tr><td><strong>Transmitters</strong></td><td>Send a command. Buttons, wall controllers, key fobs, detectors, input modules, sensors.</td><td>Battery powered, nothing to wire. <a href="/inels-home/inels-wireless/devices/transmitters.md">Transmitters</a></td></tr><tr><td><strong>Receivers</strong></td><td>Do the work. Switch units, dimmers, shutter units, fan-coil units.</td><td>Wired to the load. <a href="/inels-home/inels-wireless/devices/receivers.md">Receivers</a></td></tr><tr><td><strong>System units / gateways</strong></td><td>Connect the whole system to the app, the cloud and automation. eLAN-103, eLAN-204, RFTC-3.</td><td>Needed only for app, cloud and automation. <a href="/inels-home/inels-wireless/devices/system-units.md">System units</a></td></tr></tbody></table>

{% hint style="info" %}
**In one sentence:** a *transmitter* says "something happened", a *receiver* does something about it, and a *gateway* lets you do the same from your phone and add logic.
{% endhint %}

## Two ways to make them work together

```mermaid
flowchart LR
    T["Transmitter<br/>button, detector, sensor"] -->|"1. Direct pairing<br/>(by hand, PROG button)"| R["Receiver<br/>switch, dimmer, shutter"]
    T -.->|"2. Added to the gateway"| G["Gateway<br/>eLAN-204 / eLAN-103 / RFTC-3"]
    R -.->|"2. Added to the gateway"| G
    G --> A["App, web interface, cloud"]
    G --> L["Scenes, timers, logic, automation"]
```

### Way 1: direct pairing (transmitter → receiver)

You teach a receiver to obey one transmitter button, **by hand**, with the PROG button. No network, no app, no gateway.

* The receiver stores the pairing in its own memory, so it **keeps working** even if the gateway, router or internet is off.
* One transmitter button can control **many receivers**; one receiver can obey **many buttons** (and detectors).
* You choose a **simple function** with the number of presses: switch on, off, toggle, delayed off, dimming scenes, and so on ([Appendix B](/inels-home/inels-wireless/appendix-b-functions-by-number-of-presses.md)).

This is what [Tutorial 1](/inels-home/inels-wireless/tutorial-1-your-first-button-and-light.md) and the [Pairing reference](/inels-home/inels-wireless/pairing-and-configuration.md) teach.

### Way 2: through a gateway (app, cloud, automation)

You add transmitters and receivers to a **gateway**. Then you can:

* control everything from the **app**, the **web interface** or the **cloud**, also when you are away
* make **scenes**, **timers** and **schedules**
* build **higher logic and automation** — "when the window opens, switch the heating off", "motion at night → dim the corridor light" — that button counting cannot express
* integrate with other systems

A gateway needs a network and has to be set up; see [System units and gateways](/inels-home/inels-wireless/devices/system-units.md).

### Which one do I need?

| I want…                                                 | Use                                        |
| ------------------------------------------------------- | ------------------------------------------ |
| A wall button to switch a light                         | Direct pairing                             |
| A detector to switch a light                            | Direct pairing                             |
| The same light also from my phone                       | Direct pairing **and** add it to a gateway |
| A schedule, a scene or a condition ("only after dark")  | Gateway                                    |
| Heating zones controlled from the app                   | Gateway (RFTC thermostats)                 |
| Control that still works if Wi-Fi or the internet fails | Direct pairing                             |

Most installations use **both**: direct pairing for the everyday switching, a gateway on top for the app and the clever parts.

## Products by role

Per the iNELS Wireless catalog.

| Role                        | Products                                                                                                                                                        |
| --------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Transmitters**            | RFWB, RFGB, RFOWB wall controllers · RF KEY, RF Pilot · detectors RFMD, RFWD, RFSF, RFPD · input modules RFIM, RFSG, RFTM · sensors RFTI, RFSOU, RFSLT          |
| **Receivers**               | Switch units RFSA, RFSAI, RFUS, RFSC, RFSZ · shutter units RFJA · dimmers RFDEL, RFDA, RFDSC, RFDAC, RFDALI · fan coil RFSA-266M · RFSTI-11B-SL · valve RFATV-2 |
| **Both in one**             | Button controllers with an output: RFSK-21, RFDK-21, RFJK-22, RFMB, RFSW, RFDW, RFGS                                                                            |
| **System units / gateways** | eLAN-103, eLAN-204, RFTC-3 · also RF Touch-2 and the RFRP-20N repeater                                                                                          |

## What to read next

* **First time?** [How programming works](/inels-home/inels-wireless/how-programming-works.md), then [Tutorial 1](/inels-home/inels-wireless/tutorial-1-your-first-button-and-light.md).
* **Pairing something specific?** [Pairing reference](/inels-home/inels-wireless/pairing-and-configuration.md).
* **Setting up the app or cloud?** [System units and gateways](/inels-home/inels-wireless/devices/system-units.md).