Asterisk settings for t-online.de

Incoming and Outgoing Settings

here’s a basic asterisk configuration to place and receive calls through t-online.de, the germans leading telephone provider.

Assume your telephone number is +49 30 8151234, your username is your telephone number without ld prefix.
For example 0308151234.

In sip.conf:

[general]
register => username:password:[email protected]@tel.t-online.de/username~480

;; Deutsche Telekom AG
[t-online.de]
[email protected]
fromuser=username
secret=password
context=incoming
extension=username
type=peer
host=tel.t-online.de
fromdomain=tel.t-online.de
realm=tel.t-online.de
nat=no
directmedia=no
insecure=port,invite
canreinvite=yes
dtmfmode=inband
qualify=yes
session-timers=refuse     ; Important!
allow=!all,alaw,g722

In extensions.conf:

[incoming]
exten => username,1,Verbose(Incoming call via DTAG)
 same => n,Dial(SIP/john)
 same => n,Hangup

[trunk-dtag]
exten => _X.,1,Verbose(Outgoing call via DTAG)
 same => n,Set(CALLERID(all)=username)
 same => n,Dial(SIP/t-online.de/${EXTEN},180,rg)
 same => n,Hangup

Known issues

Telekom didn’t support session timers yet. Without “session-timers=refuse” in sip.conf calls getting dropped every 30 minutes.

If this Message occurs append “~480” to the register-line at sip.conf:

[Mar 20 23:43:49] WARNING[15603]: chan_sip.c:20749 handle_response_register: Got 423 Interval too brief for service [email protected], minimum is 480 seconds
[Mar 20 23:51:34] WARNING[15603]: chan_sip.c:20749 handle_response_register: Got 423 Interval too brief for service [email protected], minimum is 480 seconds
[Mar 20 23:59:20] WARNING[15603]: chan_sip.c:20749 handle_response_register: Got 423 Interval too brief for service [email protected], minimum is 480 seconds