In normal use, T450BT pairing mode is automatic. First time it is switched on, it goes into pairing mode at once, shown by the blue LED blinking. After first pairing, if the last used source is not on when the T450BT is switched on, it will wait about 10 seconds with the LED showing white light, then it will switch to pairing mode, with the LED turning blue, and blinking. If you want to start pairing mode manually, make sure that the headphones are switched off, then press and hold the on/off button for more than 5 seconds. The headphones will now switch on in pairing mode, shown by the blue LED blinking.