The telephone numbers of incoming calls are converted differently depending on the SIP or ISDN subscriber criteria and whether automatic outside line access is active or not.
The calling party ID is changed depending on the following parameters:
- The prefix ("call prefix" or "Cln-Prefix") that is stored for the line (default: <blank>).
- The prefix for internal connections with destination ISDN users ("internal ISDN prefix" or "Intern-Cln-Prefix" - default: '99').
- The prefix for internal connections with destination SIP users ("internal SIP prefix" or "Intern-Cln-Prefix" - default: '99').
- The prefix for external connections with destination ISDN users ("external ISDN prefix" or "Extern-Cln-Prefix" - default: <blank>).
- The prefix for external connections with destination SIP users ("external SIP prefix" or "Extern-Cln-Prefix" - default: <blank>).
The activation of automatic outside line access is taken into account by configuring the prefixes appropriately:
- If automatic outside line access is activated, the internal prefixes are typically set to the dial character that is used to reach the internal subscriber, usually '99' or '*'.
- Without automatic outside line access, the external prefixes are typically set to '0'.
The calling party ID is only extended if the incoming call has a calling party ID. If the calling party ID is blank, no prefix is attached.
It is changed as follows:
- With internal connections, the internal subscriber prefix (SIP or ISDN) is placed in front of the calling party ID.
- With external connections, depending on the (line) call prefix, the
following decision is made:
- (Line) call prefix blank: The external subscriber prefix (SIP or ISDN) is placed in front of the calling party ID.
- (Line) call prefix not blank: The internal subscriber prefix (SIP or ISDN) and the (line) call prefix is placed in front the calling party ID.
Note: A call is regarded as external if it comes from a "line". If this line is a SIP PBX line, then the call is only external if the incoming calling party ID is preceded by a "0".