How should the extended device number be used in pairing?
How should the extended device number be used in pairing?
When connecting to a master device for the first time (i.e when the channel ID is unknown) it is common to wildcard the device number and transmission type, and just specify the device type.
Once connected the slave device can store the device number and the transmission type of the master, and use these numbers to connect to the same device in future. If the upper nibble of the transmission type was used to extend the device number then the slave will have a 20 bit "extended device number" that it can use to identify the correct master - which is great news for crowded environments like gyms, marathons, and the ANT+ office!
Please note that if a display shows the device number to the user, it may show either the 2 byte device number, or the 20 bit extended device number, or possibly the device number and transmission type. These display options are all acceptable.
