You can find a useful guide regarding transactions of a Cardlink POS in a video or a PDF format below, according to your model:
A80 Ethernet: PDF (available in Greek)
A920 WiFi/GPRS: PDF (available in Greek)
A910 WiFi/GPRS: PDF (available in Greek)
D200 Mobile: PDF (available in Greek)
Verifone Vx520 Ethernet: Video (available in Greek) | PDF
Ingenico iCT220 Ethernet: Video (available in Greek) | PDF
Verifone GPRS Vx675: Video (available in Greek) | PDF
Verifone WiFi Vx675: Video (available in Greek) | PDF