Aastra Dialog 4425 IP Vision User Manual page 42

Introduction to Your Extension
42
This ring is distinctly cadenced, according to whether the incoming
call is an internal or external call. The cadence is faster for an
external call.
Note: Your facility also usually provides integrated on-hold
music, to which every external calling party either placed on
hold or parked will be connected.
MD Evolution – Dialog 4425 IP Vision