00 1 504 is the way that a telephone number in New Orleans, Louisiana, would be dialed. However, it is incorrect to call that "telephone code 001504." In quoting international telephone numbers, you should always omit the international access prefix (most commonly 00, but many countries use other prefixes) and give the number beginning with the plus symbol and the actual telephone country code, in this case +1 for North America (USA, Canada, etc.).
(The plus sign means "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but Japan uses 010, Australia uses 0011, and many other countries use different prefixes.)
+1 is the country code for North America (USA, Canada, etc.), and +1 504 is New Orleans, Louisiana, USA.
(The plus sign means "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but North America (USA, Canada, etc.) uses 011, and many other countries use different prefixes.)
Telephone area codes in the United States are always three digits.
60615 is not an area code. Area codes in the US are 3 digits and are used with telephone numbers. The postal ZIP Code 60615 is for Chicago, IL.
The telephone country code for the United States is +1.
Telephone country code +380 is Ukraine. 38067 is also a US ZIP Code (postal code) for Saulsbury, Tennessee.
Country code +1 is North America (USA, Canada, etc.), and area code +1 207 is the US state of Maine, but you have too many digits for a valid telephone number.Not a valid number.
Wake Island does not have a telephone country code, because there are no direct-dialable telephones there. All telephone access to Wake Island is handled by the US Air Force through a special operator in Hawaii.
The telephone country code for the US, Canada, and several other countries, is +1. A fax number in the US looks like any normal telephone number, with a 3-digit area code and a 7-digit local number. The plus sign in the country code means "insert your international access prefix (e.g., 00) here."
00 1 then the full ten-digit US telephone number.
Midway Island does not have a telephone country code, because it does not have any permanent inhabitants. Telephone service to Midway is provided by the US military through a special operator in Hawaii. It is not possible to direct-dial a call to Midway.
California
The most reliable way is to enter all telephone numbers in international format, beginning with the plus symbol and the country code. For US and Canadian numbers, just prefix the domestic number with telephone country code +1; for example, +1 314 555 0123. To call Australia, replace the trunk prefix 0 of the Australian domestic telephone number with telephone country code +61. For example, Queensland's area code 07 becomes +61 7.
All telephone numbers in the North American Numbering Plan, including the USA, Canada, and 18 island nations and territories in or near the Caribbean, have a total of 11 digits:Country code: 1 digit (country code +1)Area code: 3 digitsSubscriber number: 7 digits