Photo of a person bringing an access card to a digital lock

3 types of Access Control Cards commonly used in NZ in 2023

Access Control – that is, electronic locks – can be set up and configured through a host of different technologies. There are biometric such as face recognition, fingerprint readers, or even retinal scans. There is the very rudimentary method of a numberpad. This article covers the very common method of keycards you have undoubtedly used at some point in your life – swipe cards, or keycards. These are found widespread through Auckland, from offices to warehouses, and public institutions such as universities and hospitals. Even the Auckland Transport AT HOP card is a type of access card.

Photo of person using an Auckland Transport HOP bus access card

In particular we will cover the three time tested types of keycards still going strong in 2023: Wiegand cards, Magnetic Stripe cards, and RFID cards. As well as discuss their strengths and weaknesses.

Wiegand Card – polarised magnetic wires

Wiegand cards were introduced in the 1970s and are still around today. The reason why is the simple but powerful technology behind them. They function based on an electrical phenomenon called the Wiegand effect. Without diving down into the details, in short it is the generation of an electrical pulse in a wire when brought up to a magnetic field.

For the purpose of access control cards, this effect is used to read data from a keycard. The access card has a specific pattern of wires which generate a unique code when exposed to a magnetic field. The magnetic field is generated by a special Wiegand card reader.

When the card is swiped over the reader, the generated unique electrical pulse is read by the reader, and functions much like a password, or a key.

diagram of a wiegand access card showing magnetic wires


The pros of using Wiegand cards are:

  • Reliability
  • Durability
  • Security

Due to the simplicity of the design, Wiegand cards are reliable and durable, based on encased metal wires. Additionally they are secure as it is very difficult to counterfeit the unique signal from the card without duplicating it exactly.


Again due to its simplicity as well as unique operating method, there are a few drawbacks with these cards:

  • Limited storage
  • Compatibility issues
  • Cost

Most Wiegand access cards are standardised to a 26 bit storage, which is rather small. Other card technologies can store considerably more information. Some Wiegand cards have been extended to 37 bits but this is still quite limited, and it cannot grow much further due to the size of the card.

Additionally, because of its unique methodology, Wiegand cards are obviously not compatible with other readers and can be difficult to integrate into a different system. They are also slightly more expensive than some other technologies, which can be a nuisance for an organisation with hundreds or thousands of cards.

Magnetic Stripe Card

These cards are used by almost everyone on a daily basis, even if not for access control. The black stripe on the back of your credit or EFTPOS card is a magnetic stripe. These cards work by encoding data on that stripe. The stripe is made up of tiny magnetic particles, which can be written onto by a special machine.

When the card is swiped through a specialised card reader, the reader detects the magnetic field of the particles. The variances in the field let the reader successfully decode the data written on the stripe.

Magnetic Stripe Card


Magnetic stripe access cards have some advantages, especially compared to Wiegand cards:

  • Stores more data
  • More cost effective
  • Compatibility

Ultimately the biggest advantage of a magnetic stripe card is the huge amount of data it can store compared to Wiegand cards, and especially relative to their cost. They are cost effective, being relatively inexpensive to produce. This helps large organisations who need to use a lot of cards.

Compatibility is also another key strength. Magnetic stripe cards are compatible with a lot of different readers, making it easy to integrate into an existing access control system using stripe card readers.


Unfortunately everything isn’t rainbows and sunshine with magnetic stripe cards for access control. There are some weaknesses that are hard to overlook, and must be taken into consideration when building a security system.

  • Weaker Security
  • Wear and Tear

The biggest drawback of stripe cards is their relatively weaker security. The data stored in the stripe can easily be read by any card reader. It is fairly simple to copy the data from a stripe card and paste it onto a duplicate card, compromising your system. This means you will probably need to consider redundancy for your access control such as stringent access log review, and even camera verification for particularly secure areas.

Another downside of magnetic stripe cards is wear and tear. The card gets physically rubbed by the reader every time it’s used, and even though its not particularly forceful, it can add up. If the card is used multiple times every day, this means hundreds of uses over a year. High use cards can need regular replacement.

RFID Card – radio emitting wires

The third and final card type covered in this article is the RFID card. RFID (short for Radio Frequency Identification) is a technology that uses radio waves for communication between card and reader. RFID chips/cards have two components: an antenna and a microchip.

When the card is brought up to a reader, the reader powers the card with radio waves, which are caught by the antenna. The microchip sends out a unique frequency/code back to the reader. This code is then checked for authority to access the system or area.

Photo of a white plastic RFID access control card


The RFID cards have some very solid selling points, having key advantages over both magnetic stripe and Weigand cards. The RFID card is closer to the Weigand card in terms of functionality, but has some upgrades.

  • Stronger Security
  • Longer range
  • Data storage size
  • Durability

The RFID card has a huge upgrade to the original Wiegand cards. That is – storage size. This plays a part not in simply carrying more information, but also in security. The card can carry tonnes of identifying information, making a more versatile access control system.

It also provides plenty of storage space for encryption, which is needed to prevent anyone from simply copying the card. The card can output any one of thousands of encrypted codes, especially if it has a unique input, that is impossible to just copy.

Another massive advantage is the longer range with which these cards can work. If you’ve ever seen a security scanner in a supermarket or retail store go off with loud beeps, it has captured the RFID info from a chip several feet away. This is quite handy for access cards, meaning a card doesn’t necessarily need to be brought up right to the reader. You can quickly swipe the card past the reader, making it more time effective and enjoyable to use.

Lastly, the RFID circuit is fully enclosed in hard plastic. Plastic is fully invisible to radio waves, yet protects the internals from damage or wear and tear.


All these benefits of RFID cards do not come for free, otherwise you wouldn’t see any stripe cards anymore.

  • Cost of production
  • Complexity of setup

They can be summarised as higher cost. Not only the cost of production, which makes each card more expensive and can quickly add up for a large system.

But also the complexity of setting up and configuring the cards. They require more processing to initialise, and more hardware to install. As well as making sure many readers close to each other don’t interfere with one another.

Common access cards – a recap

In conclusion, modern systems use mostly one of these three types. The most common are really magnetic stripe cards due to their cost effectiveness and ease of setup. However they suffer from weaker security.

For the best security and convenience, we recommend RFID systems. Event though they are more complex and expensive to set up, it is worth it in the long run.

two security cameras; one black, one white

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