Types of PDQ Terminals

There are four primary types of PDQ (Process Data Quickly) machine or ‘chip and pin’ terminals

  • Telephone Line (PSTN – Public Switched Telephone Network) – This is the oldest and, until a few years ago, the most common type of device, it requires a physical telephone line between the PDQ modem and the bank. It’s slow, difficult and very costly to use at event sites because of the need for a dedicated physical phone line, however, once it is working it is reliable.
  • Mobile PDQ (GPRS/GSM) – Currently the most common form of PDQ, it uses a SIM card to connect to a mobile network to use GSM or GPRS to connect back to the bank. Originally seen as the go anywhere device, in the right situation they are excellent, however, they have limitations, the most obvious being they require a working mobile network to operate. At busy event sites the mobile networks rapidly become saturated and this means the devices cannot connect reliably. As they use older GPRS/GSM technology they are also very slow – it doesn’t make any difference if you try and use the device in a 4G area – it can only work using GPRS/GSM. As they use the mobile operator networks they may also incur data charges.
  • Wi-Fi PDQ – Increasingly common, this version connects to a Wi-Fi network to get its connectivity to the bank. On the surface this sounds like a great solution but there some challenges, firstly it needs a good, reliable Wi-Fi network. The second issue is that many Wi-Fi PDQs still operate on the 2.4GHz Wi-Fi spectrum which on event sites is heavily congested and suffers lots of interference making the devices unreliable. This is not helped by the relative weak Wi-Fi components in a PDQ compared to a laptop for example. It is essential to check that any Wi-Fi PDQ is capable of operating in the less congested 5GHz spectrum.
  • Wired IP PDQ – Often maligned because people think it doesn’t have a ‘wireless’ handset, but they are actually the same as all the others and have a wireless handset but it uses a physical wire (cat5) from the base station to connect to a network. In this case the network is a computer network using TCPIP and the transactions are routed in encrypted form across the internet. If a suitable network is available on an event site then this type of device is the most reliable and fastest, and there are no call charges.

All of these units look very similar and in fact can be built to operate in any of the four modes, however, because banks ‘certify’ units they generally only approve one type of connectivity in a particular device. This is slowly starting to change but the vast majority of PDQs in the market today can only operate on one type of connectivity and this is not user configurable.

On top of these aspects there is also the difference between ‘chip & pin’ and ‘contactless’. Older PDQs typically can only take ‘chip & pin’ cards whereas newer devices should also be enabled for contactless transactions.

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