- Allows you to specify what pattern of numbers that will support H.450.3 standard.
- It keeps the call from being hairpinned when being forwarded to a distance site that also forwards the call.
- example is a call forwarded to Texas to Cali, then Cali is noan, so it is forwarded to FLA.
H.450.3 takes over and connects the call from Texas to FLA.
Without H.450.3, the call would go from Texas to Cali then to FLA. This is a QOS problem to be avoided.