The entry fields "Asserted Identity" within Gateway Groups enables an outgoing Call Forward of an originally PSTN call
via a SIP Trunk.
Normally SIP provider check the calling number of an outgoing call because they are committed to ensure the correctness
of the used CLI.This is done by the network provided value "Asserted Identity".
If Call Forward is configured and an incoming call from PSTN is redirected towards the PSTN via a SIP Trunk the following
aspects must be respected.
The administrator must configure "Asserted Identity" in the following way. The first row contains the seach pattern for all
^(.*) and the second row the replaced line number (in this example +492871...) along with extension number ($1).
The PBX uses automatically as extension the number of the forwarded account.