--- 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 ms.reviewer: manager: dansimp keywords: room control system, Surface Hub ms.prod: surface-hub ms.sitesec: library author: dansimp ms.author: dansimp ms.topic: article ms.date: 07/27/2017 ms.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. | Setting | Value | | --- | --- | | Baud rate | 115200 | | Data bits | 8 | | Stop bits | 1 | | Parity | none | | Flow control | none | | Line feed | every carriage return | ## 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. | Modifier | Result | | --- | --- | | + | Increment a value | | - | Decrease a value | | = | Set a discrete value | | ? | Queries for a current value | ## Power Surface Hub can be in one of these power states. | State | Energy Star state| Description | | --- | --- | --- | | 0 | S5 | Off | | 1 | - | Power up (indeterminate) | | 2 | S3 | Sleep | | 5 | S0 | Ready | 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. | State | Energy Star state| Description | | --- | --- | --- | | 0 | S5 | Off | | 5 | S0 | Ready | For a control device, anything other than 5 / Ready should be considered off. Each PowerOn command results in two state changes and responses. | Command | State change| Response | | --- | --- | --- | | PowerOn | Device turns on (display + PC).

PC service notifies SMC that the PC is ready. | Power=0

Power=5 | | PowerOff | Device transitions to ambient state (PC on, display dim). | Power=0 | | Power? | SMC reports the last-known power state. | Power=<#> | ## 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. | Command | State change |Response | | --- | --- | --- | | Brightness+ | System management controller (SMC) sends the brightness up command.

PC service on the room control system notifies SMC of new brightness level. | Brightness = 51 | | Brightness- | SMC sends the brightness down command.

PC service notifies SMC of new brightness level. | Brightness = 50 | ## 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). | Command | State change | Response
(On in [Replacement PC mode](connect-and-display-with-surface-hub.md#replacement-pc-mode)) | | --- | --- | --- | | Volume+ | SMC sends the volume up command.

PC service notifies SMC of new volume level. | Volume = 51 | | Volume- | SMC sends the volume down command.

PC service notifies SMC of new volume level. | Volume = 50 | ## Mute for audio Audio can be muted. | Command | State change | Response | | --- | --- | --- | | AudioMute+ | SMC sends the audio mute command.

PC service notifies SMC that audio is muted. | none | ## Video source Several display sources can be used. | State | Description | | --- | --- | | 0 | Onboard PC | | 1 | DisplayPort | | 2 | HDMI | | 3 | VGA | Changes to display source can be sent by a room control system, or other system. | Command | State change | Response | | --- | --- | --- | | Source=# | SMC changes to the desired source.

PC service notifies SMC that the display source has switched. | Source=<#> | | Source+ | SMC cycles to the next active input source.

PC service notifies SMC of the current input source. | Source=<#> | | Source- | SMC cycles to the previous active input source.

PC service notifies SMC of the current input source. | Source=<#> | | Source? | SMC queries PC service for the active input source.

PC service notifies SMC of the current in;put source. | Source=<#> | ## Errors Errors are returned following the format in this table. | Error | Notes | | --- | --- | | Error: Unknown command '<input>'. | The instruction contains an unknown initial command. For example, "VOL+" would be invalid and return " Error: Unknown command 'VOL'". | | Error: Unknown operator '<input>'. | The instruction contains an unknown operator. For example, "Volume!" would be invalid and return " Error: Unknown operator '!'". | | Error: Unknown parameter '<input>'. | The instruction contains an unknown parameter. For example, "Volume=abc" would be invalid and return " Error: Unknown parameter 'abc'". | | Error: Command not available when off '<input>'. | When the Surface Hub is off, commands other than Power return this error. For example, "Volume+" would be invalid and return " Error: Command not available when off 'Volume'". | ## Related topics [Manage Microsoft Surface Hub](manage-surface-hub.md) [Microsoft Surface Hub administrator's guide](surface-hub-administrators-guide.md)