The technology described in this document can be embodied in a method that includes establishing a first wireless communication channel between a first device and a second device. The method also includes accessing, by an application executing on the first device, a transmitter of a first device to transmit to a second device one or more signals configured to cause an occurrence of an event on the second device. The one or more signals are transmitted over a second wireless communication channel between the first device and the second device. The method further includes receiving, from the second device over the first wireless communication channel, information representing a media access control (MAC) address of the first device, and storing, on a storage device accessible by the first device, a representation of the MAC address of the first device. The MAC address is associated with the second wireless communication channel.