05 - Do not honour. Ask for another form of payment
68 - Response received too late. Try again or phone Innervation Support
55 - Incorrect PIN. Ask customer to re-enter PIN
96 - System malfunction. Reset PIN Pad or call Innervation Support
91 - Issuer or switch inoperative. Contact Innervation
51 - Insufficient funds. Ask for another form of payment
TIP #1 - If the pin pad does not say 'insert' or 'swipe card', it is not connected to the system. Please check cables, restart pin pad and try again.
TIP #2 - Code 91 can mean connectivity is down - check internet access