Codes, abbreviations, numbers - can be confusing. For example you might be asked to enter your PUK code - but what is a PUK code and what does it do ?

In this article we explain the purpose of PIN, PAC and PUK codes.

Why explain them in one article instead of a different article for each ?

Well, there are two reasons:

  1. If you are like the author perhaps you find each of them confusing when spoken about separately; and
  2. PIN and Puk are very inter-related;

What do the letters PIN PAC and PUK stand for ?

PIN - Personal Identification Number;

PAC - Port Authorisation Code; (Sometimes referred to as NUC - Number Unlock Code);

PUK - Pin Unlock Key.


Many, if not all, SIM cards can be protected from unauthorised, or accidental, usage by selecting and entering your own chosen PIN.

To make a call, or send a text, your chosen PIN will be asked for - if you, or anyone trying to use your phone, do not know the PIN then the call cannot be made or text sent (or even written for that matter).

Usually, once your phone has been switched off, then switched on, during "start up" you will be asked for your PIN.

The PIN can usually be chosen and entered via the menu system of your phone.

For the Nokia 2600 (as used by this article author) the following steps:

  1. Select the Menu button;
  2. Scroll to, and select: Settings;
  3. Scroll down to, and select: Security settings;
  4. Scroll to: PIN code request - this option might even be the first option at step 3 above;
  5. Press: Select;
  6. You will see: Enter PIN code - enter a number(s) you will easily remember yourself - do not tell anyone else the number you have chosen - press OK;
  7. Your PIN code will now be set.

So now you have set your SIM card PIN number and remembered it - or have you remembered your PIN ?

Like forgetting your bank card PIN and entering the wrong PIN a certain number of times your bank card will be blocked, or "eaten" by the cash machine, and you will have to contact your bank.

If you enter your SIM card PIN number incorrectly a certain number of times in a row, your SIM card will become blocked and you will have to contact your Network Provider.

The number of attempts you have before your SIM card is blocked depends upon the Network you are on.

The number of attempts will vary from Network-to-Network and might be 3, 5, or as many as ten, attempts.

In the unfortunate event that you get the PIN number wrong and your SIM card is blocked you will then need to use a PUK number.

There is also a further "layer" that can be protected - a more advanced level of settings.

These advanced settings can be protected by a unique PIN number also, usually referred to as PIN2.

PIN2 works in the same way as PIN, but to alter any advanced settings you will be asked for PIN2.

The consequences of entering the wrong PIN2, more than the number of attempts allowed, will also result in your SIM being rendered inoperative and will require a PUK2 code from your Network Provider.

Top of page


Following on from the information above regarding PIN number, if you enter the wrong PIN more times than allocated attempts allow, your SIM card will become blocked.

In this case you will need to contact your Network Provider Customer Services and request a PUK number.

For security reasons, legally, it is only the Network Provider who can provide a PUK.

Your Network Provider will usually request some details to confirm that you are legally entitled to use the SIM Card - this is one good reason why registering your details with the Network Provider as soon as you receive your SIM card - after all, it is doubtful that you would want your car or house, keys released for a complete stranger to make use of.

If you forget your PIN2 code, for changing advanced settings, or enter the wrong PIN2 code more than the permitted number of attempts you will be required to contact your Network Provider for a PUK2 code.

Top of page.


This is a number that is unrelated to PIN and PUK but can be confused with both or either.

If you chose to transfer to a different Network Provider, maybe to make use of more competitive call or text pricing, you have the right to keep your existing phone number.

Providing you do not have a fixed term contract with your existing Network Provider, or are outside of the fixed term contract, you can request a PAC number, sometimes also referred to as a NUC (Network Unlocking Code), from your existing Network Provider.

PAC and NUC are different terms for, effectively, the same thing - where we refer to one in this article it can be interchanged with the other term.

Requesting a PAC (NUC) number is in effect cancelling your existing service arrangement.

How long does it take to receive a PAC ?

This depends on the Network Provider you are leaving

Some Networks send this through the post - so maybe 3 working days, other Networks tell you over the phone, yet others will text your PAC (NUC) to you.

What do I do with the PAC ?

You will need to give your PAC (NUC) to your new Network Provider.

Transferring your number can take a few days - if you are not told how long it takes, asking might be a good idea.

Your new Network provider might give you a temporary number to use until your existing number is formally transferred.


- Some Network Providers require your PAC at the time of connection or account/service creation - if you are unable to give your new Network Provider your PAC you might not be able to transfer your number to them;- When you transfer from one Network Provider to another - any credit on your original Network Provider will be lost so use it up if you can;- It is possible that other data, for example your contact list, may be lost during transfer;- Phone software updates and upgrades may no longer be obtainable when you transfer to a different Network Provider;- Your PAC is usually valid for 30 calendar days;- A PAC request against your phone number will void any previous request;- You cannot transfer (Port) your number to a different package on the same network as you are already on - if you wish to transfer to a different calling tariff on the same network you will need to ask your Network Provider about upgrading or changing tariff plan. hopes that this article clarifies the meaning, and purpose, of PIN PUK and PAC. As well as the drawbacks of transferring your phone number to a different Network Provider.

Top of page.

Mobile Number Portability

Mobile Number Portability (MNP) is the process followed where you can transfer from one Mobile Network to another Network Provider and keep (transfer) your existing Mobile number.

For some Network Providers it is possible to transfer your number after connection to your new Network - however, other Networks, for example Vodafone, require your PAC number before you complete your sign-up to Vodafone.

If you are thinking about transferring your Phone number to a different network it would be prudent to determine whether or not your proposed new Network requires your PAC number before connection to their network is made.

If your PAC number is required before connection to your proposed new Network and you do not have it to hand it is highly likely that you will not be able to transfer your number.

Donor and Recipient

When applying for a PAC number - your existing Network Provider is often referred to as the PAC donor.

Your new Network Provider is often referred to as the PAC recipient.

Top of page.

This article can be used on your own website, free of charge, providing this article is unaltered and the information and link in the box below is also included with the article.

Tim Austin writes articles about various aspects of the Mobile Phone industry.

More articles are available by visiting

Read About Joomla


If you would like to create your own Joomla!® powered Content Management System (CMS) website you might like to read about Joomla!® by visiting

New UJ Logo


New Zealand Philately

header copy

For images, hints and tips on New Zealand postage stamps and philately, visit . . .

logo min

mail 305433 min