Contactless payments in G8

STS’ G8:Enterprise and G8:Client applications are designed to allow merchants to accept credit and debit card payments in a variety of ways – EMV (Chip-and-PIN), magnetic stripe, keyed entry and contactless – hiding the complexity of the process from the POS system, and providing merchants with a choice of card readers and payment system providers.

Here, we describe your options when supporting contactless card payments.


G8 leverages STS’ Touchlink contactless-payments product to perform contactless transactions. Touchlink is the counterpart to STS’ Emvelink EMV payments system. Unlike Emvelink, which has its own EMV Kernel, Touchlink uses the on-board contactless kernels of the devices it supports; this is mainly to support the extremely rapid transaction processing time requirements. Touchlink provides an abstraction layer that hides the differences between the various card reader models.

G8 hides the details of accepting card payments behind its “take a payment from any card” interface. The transaction flow, including double-taps for on-device cardholder verification and fall-forward, is managed entirely by G8. Optional attendant instructions are sent to the POS as required.

G8 supports high-value contactless and on-device cardholder verification, so mobile-phone payment systems such as Apple Pay and Android Pay are supported as with any other modern contactless terminal that is compliant with current scheme rules.

G8’s support of Point-to-Point Encryption (P2PE) and Secure Reading and Exchange of Data (SRED) always includes contactless as well as EMV (Chip-and-PIN) and magnetic stripe.


Touchlink, and consequently G8, supports contactless on Ingenico devices running the RAM application, and Verifone devices running the VIPA (‘7816’) application. Touchlink will be extended to support other card readers in future.

Ingenico RAM

G8 supports contactless transactions on Ingenico devices running the RAM application. This includes most Telium 2 devices: including the iPP350 wired terminal; the iWL250 wireless/Bluetooth terminal; the iSMP and iCMP handheld devices; and the iUN/iUC unattended terminals.

As of RAM version 0970, G8 can support Mastercard PayPass 3, Visa payWave 2.1.2 and American Express ExpressPay 3.

G8 also maintains backwards compatibility with selected RAM versions, to allow G8 to be upgraded without requiring firmware updates and re-accreditations of the overall payment system.

Verifone VIPA

G8 supports contactless transactions on Verifone devices running the VIPA application (‘7816’). This includes a variety of devices: the Vx820 wired payment terminal; the Vx680 wireless/Bluetooth handheld terminal; the Vx600 handheld device; and the UX range of unattended terminals.

These devices support MasterCard PayPass 3, Visa payWave 2.1.2 and American Express ExpressPay 3.

G8 maintains backwards compatibility with selected VIPA versions, to allow G8 to be upgraded without requiring firmware updates and re-accreditations of the overall payment system.


G8 usually uses its own EMV Level 2 Kernel to perform contact EMV (Chip-and-PIN) transactions. This has a number of advantages, not least that the terminal itself does not need to have complicated software or configuration on it that requires costly maintenance. Due to the way Touchlink has to use on-board contactless kernels with the current supported devices, the contactless kernel software and configuration have had to be moved to the terminal. STS’ aim with G8 and Touchlink is to reduce the cost of this complexity for the integrator in a number of ways:

  1. G8 uses the same configuration files no matter which device any particular merchant is using, and translates this into the formats required by the device. This means that you only need to learn a single configuration format, and any of STS’ supported devices can be used. Sometimes, things are possible with one device that aren’t with another, or there are other limitations due to the way the devices work; when this occurs, G8 provides clear error messages pinpointing the problem. This means that any issues can be found and resolved before deployment.
  2. G8 maintains backwards-compatibility with older versions of device firmware wherever possible. Some manufacturers significantly change configuration or even API behaviour between different versions; equally, later versions of the firmware may support different versions of the Payment Schemes’ specifications – changing that could require acquirer re-certification. Thus it is in everyone’s interests not to have to upgrade device firmware, just to get the latest versions of G8. G8 is periodically updated to support the latest versions of firmware, but equally STS strive to ensure that G8 remains compatible with older versions of device firmware and G8’s configuration files. Thus, if you need to upgrade G8 to resolve issues or to leverage new features, you will not need to upgrade your device firmware, nor will you have to provide new configuration files.
  3. G8’s “take a payment on any card” interface naturally hides the complexities of contactless payments from any integrator. This is particularly useful with contactless, which has a separate and diverging kernel specification for each scheme (unlike EMV chip payments with its single overarching specification common to all schemes). G8 hides the divergence and different release-cycles of these specifications.
Monday, May 2, 2016