This field specifies the source of the tag data value. It can be either chip or msd.
Source
<xs:elementname="TagData"type="TagDataType"minOccurs="0"xmlns:xs="http://www.w3.org/2001/XMLSchema"><xs:annotation><xs:documentation><pxmlns="http://Hps.Exchange.PosGateway">EMV or Non-EMV tag data in TLV format</p></xs:documentation></xs:annotation></xs:element>