problem with transferred calls to certain numbers

[shizel505]

Hello, we have a long standing issue on transferred calls.
we have isdn incoming and sip outgoing, so we transfer from isdn out via sip, but it seems only certain numbers can transfer ie vodafone but not any other mobile carrier, the call is rings the mobile but there is no way audio.
i have checked public to public but does anyone know what creates this so as better to understand ??

thanks so much

[ralph]

That is strange that you can pass the call to one carrier and not another.
It's not the Public Net to Public Net setting.  That's pre-call setup.  The call would never ring the far phone.

Are you sure the calls that work are actually going out SIP?

Ralph