Config

class-map match-any VOICE
  match protocol rtp
  match protocol rtcp
  match protocol sip
policy-map VOIP
  class VOICE
  priority 256
interface Dialer1
  bandwidth inherit #because by default is 56kbps
  service-policy output VOIP 

Show

show class-map VOICE
show policy-map VOIP
show policy-map interface Dialer1 input|output