You have two options.
Standard international dialling
You dial, in the following order:
For example, Belfast number (028) 9018 0018 can be called as 00 44 28 9018 0018. Similarly, the mobile phone number 07345 123456 could be called as 00 44 7345 123456.
Shortcut for Northern Ireland landlines only
To make sure you are charged the lower rate for calling Northern Ireland landlines, instead of the full international call cost, you should use the 048 shortcut, followed by the eight-digit local phone number.
For example, Belfast (028) 9018 0018 should be dialled from the Republic as 048 9018 0018.
If you mean dialling "code", then no extra code is required, because Northern Ireland is part of the UK. All towns and cities in Northern Ireland use the code (028) followed by an 8-digit number. The (028) code is not required when calling from a landline in Northern Ireland, but is required when calling from a mobile or Great Britain. +44 28 is required for international calls to NI, including from the Republic of Ireland.
Northern Ireland is in the UK, and the international dialling code for the UK is +44.
Republic of Ireland dialling code: +353 Northern Ireland (UK) dialling code: +44 *Same regardless of where you are calling from
STD, or Subscriber Trunk Dialling, began in the UK in 1958.
The telephone country code for Ireland is +353. For Tullamore the area code is 057, but the zero is dropped when dialling from abroad. From the UK the dialling would then be: 00 353 57 followed by the local number.
forget it, haha, just google text dialling codes
The international dialling code for Ireland is 353 and for the UK (which includes England) it is 44.
STD dialling began in the UK in 1958.
In the US or Canada, dial *82 (or equivalently 1182) before any other codes or prefixes to enable sending Caller ID from a line that is blocked by default. In the UK or Ireland, dial 1470 to unblock. Other countries use other codes.
Luton's dialling code is 01582.
Your question is not clear. "STD codes" (Subscriber Trunk Dialling) is another term for telephone area codes in some countries, including the UK, Ireland, India, Pakistan, South Africa, and other formerly British countries around the world. There are tables of area codes for each country. See the related links below for examples.
The dialling code from UK to Australia is 00 61.
There is no overall calling or postal code for Kent. STD (Subscriber Trunk Dialling) telephone codes are exchange specific. Postal codes are specific to a few houses.