ISD Full Form | Full Form of ISD

ISD Full Form - International Subscriber Dialing

 International Subscriber Dialing

International Subscriber Dialing

  • ISD stands for International Subscriber Dialing. It's also called International Direct Dialing (IDD).
  • This term describes an international call made by an individual without relying on the telephone operator.
  • ISD is assigned to each country. It's a selected number.
  • A subscriber has got to add this code before the individual's phone number to make any international call.


  • In 1957 the first transatlantic direct dial telephone call was made to her penpal, Ann Morsley, in Dedham, Essex, by Sally Reed in Dedham, Massachusetts.
  • The International Numbering Plan for Telephones provides a country code as an item. Country codes are necessary if someone is dialling a phone number to form a call to a foreign nation.
  • Nation codes are dialled before the National phone number. By contract, the international phone numbers are constructed with ‘+ sign’ before the nation code.

ISD Call Rates

  • ISD calls are the most expensive calls to form as these are the International calls.
  • But few years back these calls are such a lot expensive that most of the people avoid forming an ISD call or speaking just few important words. But lately ISD calls are way cheaper compare to older times.
  • As we all know most ISD calls made from India to USA and Canada. For these countries ISD rates are minimum for the most of telecom operators.

Other Full forms of ISD

  • ISD : International Society of Dermatology
  • ISD : Indiana School for the Deaf
  • ISD : International School of Design
  • ISD : International School Dhaka
  • ISD : Instructional System Design

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