How to Choose a Proximity Time Clock

In Time and Attendance systems time clocks can be equipped with a variety of card readers. looking back more than 5 years ago bar-code cards were common but in today’s market the Radio Frequency Identification Device (RFID) has become the preferred technology . By far the most common of these RFID devices are the passive type consisting of a chip containing a small integrated circuit used for storing and processing information and and a tuned antenna fro receiving and transmitting data. When an external transmitter is near the RFID tag it become active more or less powered by the external antenna  

RFID devices are fitted to an increasing number of products particularly in the security industry. They are used to protect goods in retail outlets, increasingly they are employed in printers to ensure that genuine ink cartridges are used, the are used in access control applications to open doors. Most time and attendance systems use them as them in systems where employees carry an RFID card or tag to clock in and out each day. The common name for these devices is a proximity time clock or RFID time clock.

RFID cards are simple to use, almost indestructible, safe, relatively inexpensive reliable and very convenient. RFID devices come in a range of formats which does not usually impact performance but they do impact cost, cross application compatibility, ease of use and availability. Formats include proprietary offerings which are only available form certain manufacturers such has HID and Indala  and some which use an international standard such as the Mifare Smart-card.

When selecting a time and attendance system for your business you will need to consider compatibility with existing or intended use of access control or security systems . Your new time and attendance system should use RFID cards that are either compatible with your existing security system or it should use one of the more easily accessible RFID card systems.

If you have an existing security or access control system it is almost certain that you will be able to find a time and attendance provider using the same RFID Technology but you are more likely to find it an easier task if you are using an HID (who also make a mifare product) or Indala system. Because there are multiple options within the same technology provider  you will need to provide the time and attendance provider with a sample of your card to make sure their equipment can read the card. Once they have established suitability you can be confident that the systems will be able to use existing cards or tags which is both a convenience and a cost saving

For those with existing security systems using Mifare cards this will make the choice of time and attendance provider more complex due to the programmable nature of Mifare cards. Mifare cards are formatted with a number of programmable sectors depending on the memory capacity of the card. These sectors require a special secure electronic key to open and encode the sector and also to read that sector again. This is where the compatibility issues start. Your supplier of time and attendance will have to be able to specify the sector to which it writes and you existing cards must have enough memory to take the encoded information for both the security and time and attendance systems . Unless your both applications are from the same provider they will not be able to access any sector encoded by the others hardware. If your applications are form different suppliers it is almost certain that they will not be able to access each others hardware.

Some would argue that Mifare is the new standard and their flexibility is certainly an advantage. You can encode quite a lot of information on a Mifare Card. In a recent application my colleagues facilitated the process of including staff time and attendance, security access control, car parking station access, canteen credit and employees medical records data on the same card in a large metropolitan hospital.

If your proposed time and attendance solution is the only system using RFID technology then consider one of the simplest and most well used technologies such as HID or Indala . You will certainly be able to add access control later and not get caught out with odd standard. You may also use Mifare Card but you would be wise to opt for one of the larger memory sizes such as 4K to allow for expansion to other products.

The last factor to discuss is the cost of these technologies. While none of the  RFID technologies is expensive to produce there can be a large variation in cost. HID  and Indala tend to be more expensive and it is rare to see much variation in price from your solution provider because their cost is fixed. Mifare cards by comparison are generally purchased unencoded at a very low price and then encoded by the solution provider and this provides a greater degree of flexibility.

One final tip…the price of the cards you buy will almost certainly go up once you have purchased the system. The salesman will almost certainly give some away to secure the sale so  negotiate for additional cards of tags at the time of purchase and you will save yourself hundreds of dollars in a very short time.

James Bell

Time and Attendance Consultant