ringing signal
Telecommunications
1. The alternating current (ac) component of the alerting signal. [T1.401-1988] [T1.407-1990] 2. An ac signal applied across the network interface (NI) of such magnitude, frequency, and duration to cause an electromechanical ringer to ring. Used to alert the customer installation (CI) of an incoming call. [T1.401-1998]