This is a read-write integer controlling how many dialed digits are forwarded to the remote destination in the call setup message, with special negative values meaning default behavior, forwarding only extra digits beyond those needed to match the destination pattern, or forwarding all digits. An admin tunes this when the far-end system expects a specific number of digits rather than the full dialed string, such as an extension-only PBX expecting just the last few digits. For example, setting this to 4 on a peer connecting to an internal PBX would forward only the last four digits of a longer dialed number as the extension.