Question

What is ISD in telephonic communication?
A. Inter Subscriber Dialling
B. Inter Secure Dialling
C. International Subscriber Dialling
D. Intercom Simple Dialling

Answer 1

Hint: Telephone communication allows for communications between individuals (active users) to be carried out isolated by about any distance. ISD is identified as an International Direct Dialling (IDD) is an overseas telephone call that a telephone customer directly dials.

Complete step by step solution:
A telephone conversation is a type of oral contact carried out between two people in which they express their thoughts and opinions with each other. In other words, a telephone call is the contact that takes place between two people with the aid of the phone.

A foreign telephone call that is dialled directly by a telephone subscriber rather than a telephone operator is imposed by international direct dialling (IDD) or international subscriber dialling (ISD). Calls are started by dialling the international call code for the country of origin, the country code for the country of destination and, finally, the national telephone number for the country of destination.

The international call prefix is omitted when phone numbers are reported for international use, as well as the number should begin with a plus sign (+) preceded by the code of the country calling.

Hence, the correct option is C.

Note: In this question we need to determine the full form of ISD. That implies there must be three words and the words must be started with I, S, and D respectively. In the options it can be seen that all the options contain three words starting with I, S, and D respectively. Therefore, we need to go through telephonic communication in order to find the correct full form. Know that ISD is also termed as IDD, the International Direct Dialling. The recipient's phone automatically answers the call when you put an intercom call with mute enabled (whisper mode).