windows-itpro-docs/devices/surface-hub/use-room-control-system-with-surface-hub.md

---
title: Using a room control system (Surface Hub)
description: Room control systems can be used with your Microsoft Surface Hub.
ms.assetid: DC365002-6B35-45C5-A2B8-3E1EB0CB8B50
keywords: room control system, Surface Hub
ms.prod: w10
ms.mktglfcycl: manage
ms.sitesec: library
ms.pagetype: surfacehub
author: jdeckerMS
localizationpriority: medium
---

# Using a room control system (Surface Hub)


Room control systems can be used with your Microsoft Surface Hub.

Using a room control system with your Surface Hub involves connecting room control hardware to the Surface Hub, usually through the RJ11 serial port on the bottom of the Surface Hub.

## Terminal settings

To connect to a room control system control panel, you don't need to configure any terminal settings on the Surface Hub. If you want to connect a PC or laptop to your Surface Hub and send serial commands from the Surface Hub, you can use a terminal emulator program like Tera Term or PuTTY. 

<table>
<colgroup>
<col width="50%" />
<col width="50%" />
</colgroup>
<thead>
<tr class="header">
<th align="left">Setting</th>
<th align="left">Value</th>
</tr>
</thead>
<tbody>
<tr class="odd">
<td align="left"><p>Baud rate</p></td>
<td align="left"><p>115200</p></td>
</tr>
<tr class="even">
<td align="left"><p>Data bits</p></td>
<td align="left"><p>8</p></td>
</tr>
<tr class="odd">
<td align="left"><p>Stop bits</p></td>
<td align="left"><p>1</p></td>
</tr>
<tr class="even">
<td align="left"><p>Parity</p></td>
<td align="left"><p>none</p></td>
</tr>
<tr class="odd">
<td align="left"><p>Flow control</p></td>
<td align="left"><p>none</p></td>
</tr>
<tr class="odd">
<td align="left"><p>Line feed</p></td>
<td align="left"><p>every carriage return</p></td>
</tr>
</tbody>
</table>

 

## Wiring diagram

You can use a standard RJ-11 (6P6C) connector to connect the Surface Hub serial port to a room control system. This is the recommended method. You can also use an RJ-11 4-conductor cable, but we do not recommend this method.

This diagram shows the correct pinout used for an RJ-11 (6P6C) to DB9 cable.

![Image showing the wiring diagram.](images/room-control-wiring-diagram.png)

## Command sets

Room control systems use common meeting-room scenarios for commands. Commands originate from the room control system, and are communicated over a serial connection to a Surface Hub. Commands are ASCII based, and the Surface Hub will acknowledge when state changes occur.

The following command modifiers are available. Commands terminate with a new line character (/n). Responses can come at any time in response to state changes not triggered directly by a management port command.

<table>
<colgroup>
<col width="50%" />
<col width="50%" />
</colgroup>
<thead>
<tr class="header">
<th align="left">Modifier</th>
<th align="left">Result</th>
</tr>
</thead>
<tbody>
<tr class="odd">
<td align="left"><p>+</p></td>
<td align="left"><p>Increment a value</p></td>
</tr>
<tr class="even">
<td align="left"><p>-</p></td>
<td align="left"><p>Decrease a value</p></td>
</tr>
<tr class="odd">
<td align="left"><p>=</p></td>
<td align="left"><p>Set a discrete value</p></td>
</tr>
<tr class="even">
<td align="left"><p>?</p></td>
<td align="left"><p>Queries for a current value</p></td>
</tr>
</tbody>
</table>

 

## Power

Surface Hub can be in one of these power states.

<table>
<colgroup>
<col width="33%" />
<col width="33%" />
<col width="33%" />
</colgroup>
<thead>
<tr class="header">
<th align="left">State</th>
<th align="left">Energy Star state</th>
<th align="left">Description</th>
</tr>
</thead>
<tbody>
<tr class="odd">
<td align="left"><p>0</p></td>
<td align="left"><p>S5</p></td>
<td align="left"><p>Off</p></td>
</tr>
<tr class="even">
<td align="left"><p>1</p></td>
<td align="left"><p>-</p></td>
<td align="left"><p>Power up (indeterminate)</p></td>
</tr>
<tr class="odd">
<td align="left"><p>2</p></td>
<td align="left"><p>S3</p></td>
<td align="left"><p>Sleep</p></td>
</tr>
<tr class="even">
<td align="left"><p>3</p></td>
<td align="left"><p>S0</p></td>
<td align="left"><p>Resting</p></td>
</tr>
<tr class="odd">
<td align="left"><p>4</p></td>
<td align="left"><p>S0</p></td>
<td align="left"><p>Ambient</p></td>
</tr>
<tr class="even">
<td align="left"><p>5</p></td>
<td align="left"><p>S0</p></td>
<td align="left"><p>Ready</p></td>
</tr>
</tbody>
</table>

In Replacement PC mode, the power states are only Ready and Off and only change the display. The management port can't be used to power on the replacement PC. 

<table>
<colgroup>
<col width="33%" />
<col width="33%" />
<col width="33%" />
</colgroup>
<thead>
<tr class="header">
<th align="left">State</th>
<th align="left">Energy Star state</th>
<th align="left">Description</th>
</tr>
</thead>
<tbody>
<tr class="odd">
<td align="left"><p>0</p></td>
<td align="left"><p>S5</p></td>
<td align="left"><p>Off</p></td>
</tr>
<tr class="even">
<td align="left"><p>5</p></td>
<td align="left"><p>S0</p></td>
<td align="left"><p>Ready</p></td>
</tr>
</tbody>
</table>

For a control device, anything other than 5 / Ready should be considered off. Each PowerOn command results in two state changes and reponses. 

<table>
<colgroup>
<col width="33%" />
<col width="33%" />
<col width="33%" />
</colgroup>
<thead>
<tr class="header">
<th align="left">Command</th>
<th align="left">State change</th>
<th align="left">Response</th>
</tr>
</thead>
<tbody>
<tr class="odd">
<td align="left"><p>PowerOn</p></td>
<td align="left"><p>Device turns on (display + PC).</p><p>PC service notifies SMC that the PC is ready.</p></td>
<td align="left"><p>Power=0</p><p>Power=5</p></td>
</tr>

<tr class="even">
<td align="left"><p>PowerOff</p></td>
<td align="left"><p>Device transitions to ambient state (PC on, display dim).</p></td>
<td align="left"><p>Power=0</p></td>
</tr>
<tr class="even">
<td align="left"><p>Power?</p></td>
<td align="left"><p>SMC reports the last-known power state.</p></td>
<td align="left"><p>Power=<#></p></td>
</tr>
</tbody>
</table>


## Brightness

The current brightness level is a range from 0 to 100.

Changes to brightness levels can be sent by a room control system, or other system.

<table>
<colgroup>
<col width="33%" />
<col width="33%" />
<col width="33%" />
</colgroup>
<thead>
<tr class="header">
<th align="left">Command</th>
<th align="left">State change</th>
<th align="left">Response</th>
</tr>
</thead>
<tbody>
<tr class="odd">
<td align="left"><p>Brightness+</p></td>
<td align="left"><p>System management controller (SMC) sends the brightness up command.</p>
<p>PC service on the room control system notifies SMC of new brightness level.</p></td>
<td align="left"><p>Brightness = 51</p></td>
</tr>
<tr class="even">
<td align="left"><p>Brightness-</p></td>
<td align="left"><p>SMC sends the brightness down command.</p>
<p>PC service notifies SMC of new brightness level.</p></td>
<td align="left"><p>Brightness = 50</p></td>
</tr>
</tbody>
</table> 

## Volume

The current volume level is a range from 0 to 100.

Changes to volume levels can be sent by a room control system, or other system.

>[!NOTE]
>The Volume command will only control the volume for embedded or Replacement PC mode, not from [Guest sources](connect-and-display-with-surface-hub.md).

<table>
<colgroup>
<col width="33%" />
<col width="33%" />
<col width="33%" />
</colgroup>
<thead>
<tr class="header">
<th align="left">Command</th>
<th align="left">State change</th>
<th align="left">Response</br>(On in [Replacement PC mode](connect-and-display-with-surface-hub.md#replacement-pc-mode))</th>
</tr>
</thead>
<tbody>
<tr class="odd">
<td align="left"><p>Volume+</p></td>
<td align="left"><p>SMC sends the volume up command.</p>
<p>PC service notifies SMC of new volume level.</p></td>
<td align="left"><p>Volume = 51</p></td>
</tr>
<tr class="even">
<td align="left"><p>Volume-</p></td>
<td align="left"><p>SMC sends the volume down command.</p>
<p>PC service notifies SMC of new volume level.</p></td>
<td align="left"><p>Volume = 50</p></td>
</tr>
</tbody>
</table>

 

## Mute for audio

Audio can be muted.

<table>
<colgroup>
<col width="33%" />
<col width="33%" />
<col width="33%" />
</colgroup>
<thead>
<tr class="header">
<th align="left">Command</th>
<th align="left">State change</th>
<th align="left">Response</th>
</tr>
</thead>
<tbody>
<tr class="odd">
<td align="left"><p>AudioMute+</p></td>
<td align="left"><p>SMC sends the audio mute command.</p>
<p>PC service notifies SMC that audio is muted.</p></td>
<td align="left"><p>none</p></td>
</tr>
</tbody>
</table>

 

## Video source

Several display sources can be used.

<table>
<colgroup>
<col width="50%" />
<col width="50%" />
</colgroup>
<thead>
<tr class="header">
<th align="left">State</th>
<th align="left">Description</th>
</tr>
</thead>
<tbody>
<tr class="odd">
<td align="left"><p>0</p></td>
<td align="left"><p>Onboard PC</p></td>
</tr>
<tr class="even">
<td align="left"><p>1</p></td>
<td align="left"><p>DisplayPort</p></td>
</tr>
<tr class="odd">
<td align="left"><p>2</p></td>
<td align="left"><p>HDMI</p></td>
</tr>
<tr class="even">
<td align="left"><p>3</p></td>
<td align="left"><p>VGA</p></td>
</tr>
</tbody>
</table>

 

Changes to display source can be sent by a room control system, or other system.

<table>
<colgroup>
<col width="33%" />
<col width="33%" />
<col width="33%" />
</colgroup>
<thead>
<tr class="header">
<th align="left">Command</th>
<th align="left">State change</th>
<th align="left">Response</th>
</tr>
</thead>
<tbody>
<tr class="odd">
<td align="left"><p>Source=#</p></td>
<td align="left"><p>SMC changes to the desired source.</p>
<p>PC service notifies SMC that the display source has switched.</p></td>
<td align="left"><p>Source=&lt;#&gt;</p></td>
</tr>
<tr class="even">
<td align="left"><p>Source+</p></td>
<td align="left"><p>SMC cycles to the next active input source.</p>
<p>PC service notifies SMC of the current input source.</p></td>
<td align="left"><p>Source=&lt;#&gt;</p></td>
</tr>
<tr class="odd">
<td align="left"><p>Source-</p></td>
<td align="left"><p>SMC cycles to the previous active input source.</p>
<p>PC service notifies SMC of the current input source.</p></td>
<td align="left"><p>Source=&lt;#&gt;</p></td>
</tr>
<tr class="even">
<td align="left"><p>Source?</p></td>
<td align="left"><p>SMC queries PC service for the active input source.</p>
<p>PC service notifies SMC of the current in;put source.</p></td>
<td align="left"><p>Source=&lt;#&gt;</p></td>
</tr>
</tbody>
</table>

## Errors

Errors are returned following the format in this table.

<table>
<colgroup>
<col width="50%" />
<col width="50%" />
</colgroup>
<thead>
<tr class="header">
<th align="left">Error</th>
<th align="left">Notes</th>
</tr>
</thead>
<tbody>
<tr class="odd">
<td align="left"><p>Error: Unknown command '&lt;input&gt;'.</p></td>
<td align="left"><p>The instruction contains an unknown initial command. For example, &quot;VOL+&quot; would be invalid and return &quot; Error: Unknown command 'VOL'&quot;.</p></td>
</tr>
<tr class="even">
<td align="left"><p>Error: Unknown operator '&lt;input&gt;'.</p></td>
<td align="left"><p>The instruction contains an unknown operator. For example, &quot;Volume!&quot; would be invalid and return &quot; Error: Unknown operator '!'&quot;.</p></td>
</tr>
<tr class="odd">
<td align="left"><p>Error: Unknown parameter '&lt;input&gt;'.</p></td>
<td align="left"><p>The instruction contains an unknown parameter. For example, &quot;Volume=abc&quot; would be invalid and return &quot; Error: Unknown parameter 'abc'&quot;.</p></td>
</tr>
<tr class="even">
<td align="left"><p>Error: Command not available when off '&lt;input&gt;'.</p></td>
<td align="left"><p>When the Surface Hub is off, commands other than Power return this error. For example, &quot;Volume+&quot; would be invalid and return &quot; Error: Command not available when off 'Volume'&quot;.</p></td>
</tr>
</tbody>
</table>

 

## Related topics


[Manage Microsoft Surface Hub](manage-surface-hub.md)

[Microsoft Surface Hub administrator's guide](surface-hub-administrators-guide.md)