By default you won´t hear any dialtones when dialing an ISDN number through your Asterisk box. Only after the call is answered or rejected by the PSTN you will be able to hear anything.
This behaviour is likely to cause irritation to users accustomed to conventional dialtones and may also cause problems on some ISDN calls where you have to dial additional numbers before the final destination is reached.
WIth the CAPI 2.0 implementation chan_capi
it is easy to change this behaviour back to the old-fashioned way simply by adding /ob
immediately after the CAPI dial string. For example: CAPI/contr1/0018394873767/ob
will call the given number in early B3
mode with overlapped sending
of numbers. If you use the PBX manager
Web-GUI, simply change the Custom Dialstring
of your CAPI trunk to:CAPI/contr1/$/ob
Restart Asterisk, dial an ISDN number and listen to these beautiful dial tones!