Answer: Please see below as the answer is self-explanatory
Explanation:
In a telephone system, we call signaling to all signals that are originated within a telephony circuit, that are not part of the conversation between the calling parties.
We include in this broad category, the signal generated by the calling party when he picks up the phone, the call tone sent to him by the switch (or the busy tone if the call can't be established due to blocking), the digits that identify the called party, the ringing signal that informs the called party that someone is trying to reach him for a call, among others like are defined in the SS7 or the different 2G/3G/4G Cellular standards.
The importance of the signalling is pretty obvious; without these signals, it will be virtually impossible to set up a connection between the two parties.