SEDE A:

Trunk Name: SedeASedeB
host=IP SEDE B
username=SedeASedeB
fromuser=SedeASedeB
secret=XXXXXXX
type=friend
disallow=all
allow=g729
qualify=yes
nat=no
context=from-internal

SEDE B:

Trunk Name: SedeASedeB
host=IP SEDE A
username=SedeASedeB
fromuser=SedeASedeB
secret=XXXXXXX
type=friend
disallow=all
allow=g729
qualify=yes
nat=no
context=from-internal