If the display is from the late 90's, then it is probably an Ag Leader YM2000 with a Case/IH sticker on it. In order to log yield you will need a GPS receiver plus a data card. Be advised that if it is a YM2000, you'll need an SRAM card. In order to read the SRAM, you will need a computer with Windows 95/98 or, if you only have an XP machine, a special card reader from Envoy Data (cost= $429.00). Reading data from SRAM's has become a real pain in the arse!