Here’s my company Asterisk’s extensions.conf :

```
[poste-interne]
; allow internal phones to communicate between them
exten => 3250,1,Dial(SIP/3250,,TtHhXx)
exten => 3251,1,Dial(SIP/3251,,TtHhXx)
exten => 3252,1,Dial(SIP/3252,,TtHhXx)
exten => 3253,1,Dial(SIP/3253,,TtHhXx)
exten => 3254,1,Dial(SIP/3254,,TtHhXx)
exten => 3255,1,Dial(SIP/3255,,TtHhXx)
exten => 3256,1,Dial(SIP/3256,,TtHhXx)
exten => 3257,1,Dial(SIP/3257,,TtHhXx)
exten => 3258,1,Dial(SIP/3258,,TtHhXx)
[poste-to-ovh-2]
; appel interne
include => poste-interne
;appel sortant
exten => _X.,1,Dial(SIP/${EXTEN}@ovh-out-250)
[poste-to-ovh-3]
; appel interne
include => poste-interne
;appel sortant
exten => _X.,1,Dial(SIP/${EXTEN}@ovh-out-251)
[poste-to-ovh-4]
; appel interne
include => poste-interne
;appel sortant
exten => _X.,1,Dial(SIP/${EXTEN}@ovh-out-252)
[poste-to-ovh-5]
; appel interne
include => poste-interne
;appel sortant
exten => _X.,1,Dial(SIP/${EXTEN}@ovh-out-253)
[poste-to-ovh-6]
; appel interne
include => poste-interne
;appel sortant
exten => _X.,1,Dial(SIP/${EXTEN}@ovh-out-254)
[poste-to-ovh-7]
; appel interne
include => poste-interne
;appel sortant
exten => _X.,1,Dial(SIP/${EXTEN}@ovh-out-255)
[poste-to-ovh-8]
; appel interne
include => poste-interne
;appel sortant
exten => _X.,1,Dial(SIP/${EXTEN}@ovh-out-256)
[poste-to-ovh-9]
; appel interne
include => poste-interne
;appel sortant
exten => _X.,1,Dial(SIP/${EXTEN}@ovh-out-257)
[poste-to-ovh-10]
; appel interne
include => poste-interne
;appel sortant
exten => _X.,1,Dial(SIP/${EXTEN}@ovh-out-258)
[ovh-in]
exten => _X.,1,GoToIf($[${EXTEN}=3249]?fax-in,3249,1)
exten => _X.,2,GoToIf($[${EXTEN}=3250]?3250,3250,1)
exten => _X.,3,GoToIf($[${EXTEN}=3251]?3251,3251,1)
exten => _X.,4,GoToIf($[${EXTEN}=3252]?3252,3252,1)
exten => _X.,5,GoToIf($[${EXTEN}=3253]?3253,3253,1)
exten => _X.,6,GoToIf($[${EXTEN}=3254]?3254,3254,1)
exten => _X.,7,GoToIf($[${EXTEN}=3255]?3255,3255,1)
exten => _X.,8,GoToIf($[${EXTEN}=3256]?3256,3256,1)
exten => _X.,9,GoToIf($[${EXTEN}=3257]?3257,3257,1)
exten => _X.,10,GoToIf($[${EXTEN}=3258]?3258,3258,1)
[3250]
exten => _X.,1,Answer
exten => _X.,2,Dial(SIP/3250,,TtHhXx)
exten => _X.,3,Hangup
[3251]
exten => _X.,1,Answer
exten => _X.,2,Dial(SIP/3251,,TtHhXx)
exten => _X.,3,Hangup
[3252]
exten => _X.,1,Answer
exten => _X.,2,Dial(SIP/3252,,TtHhXx)
exten => _X.,3,Hangup
[3253]
exten => _X.,1,Answer
exten => _X.,2,Dial(SIP/3253,,TtHhXx)
exten => _X.,3,Hangup
[3254]
exten => _X.,1,Answer
exten => _X.,2,Dial(SIP/3254,,TtHhXx)
exten => _X.,3,Hangup
[3255]
exten => _X.,1,Answer
exten => _X.,2,Dial(SIP/3255,,TtHhXx)0
exten => _X.,3,Hangup
[3256]
exten => _X.,1,Answer
exten => _X.,2,Dial(SIP/3256,,TtHhXx)
exten => _X.,3,Hangup
[3257]
exten => _X.,1,Answer
exten => _X.,2,Dial(SIP/3257,,TtHhXx)
exten => _X.,3,Hangup
[3258]
exten => _X.,1,Answer
exten => _X.,2,Dial(SIP/3258,,TtHhXx)
exten => _X.,3,Hangup
```

I hope you’ll find something…