Sennheiser VMX 100 3in1 Bedienungshandbuch page 13

Then switch on the headset (details on page 15) and pair
it to your mobile phone. For details and information on
how to pair to another Bluetooth device see page 17.
ON
Put the headset on your ear.
(un)muting (p. 23)
ending calls (p.21)
redialling (p. 20)
VMX 100
OK
Keyword
0000
accepting calls (p. 19)
voice dialling (p.20)
volume (p. 22)
13