The full form of ISD is International Subscriber Dialing. An ISD code is used to make international calls from anywhere in the World. These calls can be directly dialed by the telephone subscribers or an individual without the need to depend on any telephone operator. ISD is also referred to as International Direct Dialing (IDD).

What is the Full Form of ISD?

International Subscriber Dialing is the full form of the ISD. Every country is assigned a unique ISD code. Whenever an individual wants to make an international call, then he/she must add that unique ISD code of the particular country as a prefix before the phone number of the dialed individual.

Characteristics of ISD

The Characteristics of ISD are showing below:

• ISD code helps in accessing the satellites of other countries and thereby facilitates connecting with them.
• This unique code must be added before the telephone numbers in order to make various international calls.
• The sequence required to dial an international number is : International access code – Country code – Telephone number. This international access code differs from country to country. The ‘+’ sign placed before the country code means – you should add the international access code of the country from where you are dialing. Nowadays , we can simply add the ‘+’ sign before the country code without the need of adding the international prefix.
• An example of ISD code – The ISD code of India is +91.

History of ISD

The facts related to the history of ISD is given below:

• The first direct dial telephone call was made in Dedham in the year 1957 with the use of ISD concept.
• The term ISD was used back in Australia and United Kingdom which was later changed to IDD.
• An United Nations organization , The International Telecommunications Union (ITU) assigns the unique country codes.
• This organization has its headquarters located in Geneva.

Benefits of ISD

The benefits of ISD are showing below:

• ISD codes help in making a telephone call to a foreign nation. Thus, those people residing in foreign countries can be easily contacted with the help of ISD codes.
• These direct calling helps in reducing call costs and also acts as time savers for all the people across the Globe.
• It is the fastest and the easiest way to communicate with any people sitting in any corner of the World. Thus, they helping in bringing the World closer.

Thus, with the advent of ISD codes making of International calls have been much easier, quicker and thereby benefiting the entire World.International Subscriber Dialing (ISD) has revolutionized the way we connect with the world, breaking down geographical barriers and bringing people closer together. From its humble beginnings as a manual, operator-assisted service to today’s seamless, automated system, ISD has played a pivotal role in shaping the global communication landscape.