The serial number retrieved from the PIN pad.
Your PIN pad will have a function that will return the PIN pad serial number. This number is used to identify the key being used by the PIN pad device to the Paymentech transaction sever, and is required to be sent in every transaction.
All PIN pad serial numbers MUST be unique. You must update the PinPadSerialNumbers property with a new value retrieved from the PIN pad device before each transaction.
All PIN Pad Serial Numbers can be variable in length, but must be a minimum of 9-bytes long, and a maximum of 16-bytes long.
The serial number of a PIN pad is usually printed on the label on the bottom of the unit. The PIN pad may also include the option of displaying the serial number on the screen or returning it through a COM interface. Please see the developer documentation for your specific PIN pad for more information.