Proximity Time Clocks - Which Format Should You Choose?

 Proximity Time Clocks - Which Card Format 

Should You Use?

There are dozens of proximity (RFID) cards available, and they are incompatible with each other and have their own pros and cons, so the answer to this question is best answered with a few more questions.

Do you have an access control system?  

If you do then it is best to select a time clock system that can use the same card format. This way, employees are not required to carry two different cards.

If you don't have an access control system, is it possible you will invest in one? 

If you answered yes to this question, it is possible that you can kill two birds with one stone depending on your access requirements. 

If the access requirement is for a single door, then many time clocks will control an entry door with the addition of an electric lock.

In any case, if access control is on the agenda, then it will be best to select a card format which is well supported in the security industry. More on this later.

If you believe it is unlikely that you will ever implement access control, then the format used by your new proximity time clock system will more likely be influenced by the ongoing costs of replacement cards and the ease of use of the system.

So what are the different formats?

There are many formats including HID, Indala, EM, Logic, Mifare, Indala and a host of others. Most of these manufacturers have multip,e card formats including a Smartcard product. Each of them has their own proprietary encoding so that a card of one format will not work on a reader with another. Even when they are using the same technology, such as smartcards, these use a proprietary key which prevents access by readers from other manufacturers.

EM 125 Khz Format From a time and attendance perspective where no access control is currently used or required in the future the ideal format is probably the EM format. These are less expensive and, when purchased from the same supplier, you can be confident that the numbers will always be unique. This makes it easy to track card numbers.

HID 125 Khz Format This is a more expensive alternative in general. The cards have a site or "facility" code, and while most employee time clocks ignore this site code, it is easy to end up with duplicated card numbers. Generally, these cards are encoded on demand so they must be pre-ordered using a site code and a number series. Someone needs to keep track of what cards have been ordered or purchased, and that will often go astray.

MIFARE Format These are often called smartcards as they have a readable/writeable memory. The card can be programmed with multiple "Keys" so a few different applications can encode specific data on the car in sectors only accessible with the security key. So the card can be used, in theory, for multiple applications from multiple providers. In reality, though, it is difficult in practice to actually get collaboration from different providers to install their various keys and data on the card. They can b more trouble than they are worth for SME's.

The other formats are mostly similar to the HID format in that they use site codes and card numbers need to be managed for the best results. 

SECURITY The lack of real security in the products is surprising. Take a look at our security article at this link for more details. Fortunately, for time and attendance purposes, the security risk is minimal, so this is only a factor if you intend to add access control down the track, and you would like a more secure application.

Tips for Time Clock Users

If you already have an access control system, ask your time clock supplier if their hardware supports the current card format and if so, send them a card sample so they can test it.

The most common card types supported by employee time clocks are EM, HID and Smartcard.

If you do not require access control, then the most likely choice would end up being EM if not just for the fact that this is the most common format used by employee time clocks.

If you require access control in the future, the HOD or Smart Car option would be better.

If you may require high-security access control, then there are very secure smartcard options available.

The Time & Attendance Consultant