ISD is for International Calls, where as STD is for local calls.
"ISD" stands for International Subscriber Dialing. An ISD code is a country code, or a country code and city code, often quoted with the local international access prefix. For example, the country code and city code for London, England, UK, is +44 20, so in many countries people will quote the ISD code for London as 004420. However, it is more appropriate to quote it as +44 20, since different countries use different prefixes for outbound international calls.
Close, but not quite. ISD stands for International Subscriber Dialing.The ISD code is more generally known as the telephone country code, or the country code and city code (area code).
The ISD code 00317 corresponds to the country of Bhutan. ISD codes, or International Subscriber Dialing codes, are used to identify countries in international telephone dialing. Bhutan's unique code allows for direct dialing to the country from abroad.
ISD means International Subscriber dialling
The telephone country code for Mozambique is +258. The plus sign means "insert your local international dialing prefix here."
PCO - Public Call Office STD - subscriber trunk dialing ISD - International Subscriber Dialing
0017 is not a country code.
international subscribers dialling
Country code +975 is Bhutan.
Syria
Dial the ISD code to US (001) and then dial the number you wish. There are several different area codes for different parts of Missouri.