interface t1 0/1 
  description OLD_PBX_OUTBOUND_PRI_1
  tdm-group 1 timeslots 1-24
  no shutdown
!
interface t1 0/2 
  description OLD_PBX_OUTBOUND_PRI_2
  tdm-group 1 timeslots 1-24
  no shutdown
!
interface t1 0/3
  description OLD_PBX_INBOUND_PRI
  tdm-group 1 timeslots 1-24
  no shutdown
!
interface pri 1
  description PBX Outbound PRI 1
  role network b-channel-restarts enable
  isdn name-delivery setup
  connect t1 0/1 tdm-group 1
  no shutdown
!
interface pri 2
  description PBX Outbound PRI 2
  role network b-channel-restarts enable
  isdn name-delivery setup
  connect t1 0/2 tdm-group 1
  no shutdown
!
interface pri 3
  description PBX Inbound PRI
  role network b-channel-restarts enable
  isdn name-delivery setup
  connect t1 0/3 tdm-group 1
  no shutdown
!
isdn-group 1
  description "Old PBX Outbound"
  connect pri 1
  connect pri 2
!
isdn-group 2
  description "Old PBX Inbound"
  connect pri 3
!
voice trunk T01 type isdn
  description "Old PBX Outbound"
  resource-selection linear ascending
  connect isdn-group 1
!
voice trunk T02 type isdn
  description "Old PBX Inbound"
  resource-selection linear ascending
  connect isdn-group 2
!
voice trunk T03 type sip
  (already working)
!
voice grouped-trunk OLD_PBX_OUTBOUND
  trunk T01
!
voice grouped-trunk OLD_PBX_INBOUND
  trunk T02
  accept 898 cost 0
  accept 899 cost 0
!
voice grouped-trunk SIP
  trunk T03
  accept [1]4]XX cost 0