extensions.conf for a Teams SBC

extensions.conf

[default]
exten = s,1,Noop
 same = n,Playback(tt-somethingwrong)

[teams]
exten = _+X.,1,Noop(PSTN)
 same = n,Dial(PJSIP/${EXTEN}@speakup)
 same = n,HangUp()

; to respond on incoming SIP Options Packates with an "200 OK"
exten = teams-out,1,HangUp()

; to allow Remote Attended Transfers
exten = external_replaces,1,NoOp()
exten = s,1,Dial(PJSIP/teams-in/${SIPREFERTOHDR})

[inbound]
exten = +12025551234,1,NoOp(Incoming call from PSTN. Routing to Teams)
 same = n,Progress()
 same = n,set(CALLERID(all)="${CALLERID(num)}" <${CALLERID(num)}>)
 same = n,Dial(PJSIP/${EXTEN}@teams-out)
 same = n,Hangup()