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 IO pin service makes it possible for another device such as a smartphone to communicate with other electronic 'things' connected to a @boardname@'s edge connector. You could for example, use your smartphone to switch on or off a light which is connected to the @boardname@ or your smartphone could receive data collected from a sensor connected to the @boardname@. In fact you could do both of these things at the same time since the Bluetooth IO pin service lets you interact with multiple 'pins' on the edge conector in different ways all at the same time.
For more advanced information on the @boardname@ Bluetooth IO pin service including information on using a smartphone, see the [Lancaster University @boardname@ runtime technical documentation](http://lancaster-university.github.io/microbit-docs/ble/iopin-service/)
