For another device like a smartphone to use any of the Bluetooth "services" which the @boardname@ has, it must first be [paired with the @boardname@](/reference/bluetooth/bluetooth-pairing). Once paired, the other device may connect to the @boardname@ and exchange data relating to many of the @boardname@'s features.
The Bluetooth LED service allows another device such as a smartphone to send short text strings or patterns over a Bluetooth connection to a @boardname@ for display on its LED matrix. Text will scroll across the @boardname@ and the speed at which it scrolls can also be controlled using the Bluetooth LED service. Devices using the LED service may also read the current state of the @boardname@'s LED matrix.
So you could, for example, draw a smiley face in a smartphone app and at the press of a button, have it magically appear on your @boardname@ on the other side of the room. Or you could program your smartphone to send a message to your @boardname@ whenever your phone receives an email, SMS or social media message so you could wear your @boardname@ like a smart watch and leave your phone in your bag.
For more advanced information on the @boardname@ Bluetooth LED service including information on using a smartphone, see the [Lancaster University @boardname@ runtime technical documentation](http://lancaster-university.github.io/microbit-docs/ble/led-service/)
