sip_providers.conf:

[NeoPhoneX-in]
type=friend
context=disa-request
canreinvite=no
fromdomain=193.91.75.213
defaultuser=06213803099
fromuser=06213803099
secret=123456
host=193.91.75.213
insecure=port,invite
pedantic=no
qualify=yes
nat=force_rport,comedia
disallow=all
allow=ulaw
allow=alaw

sip_registers.conf
;NeoPhoneX
register => 06213803099:123456@193.91.75.213