vlan voice

[Domex]

Hello the carrier I use, sent me the vlan settings for voice and data. FTTH.

VLan: 835(data)
VLan: 836(voice)
Protocol: PPPoE
PPPoE usr: benvenuto
PPPoE pwd: ospite
Encapsulation: LLC
NAT: enabled
COS data: 0 (IEEE 802.1 P)
COS voice: 5 (IEEE 802.1 P)

I configured succesfully the vlan data but the voice I did at the same way (changed the vlan ID) never goes up.
Can someone help me?