The utility model is suitable for a weighing -appliance field provides discernment interface system weighs, discernment interface system weighs is used for truck scale weighing system, the truck scale is provided with the output interface of the data of weighing, discernment interface system weighs is used for reading the output data of truck scale, a serial communication port, discernment interface system weighs is provided with the interface arrangement who is used for with the butt joint of the output interface of truck scale, interface arrangement is provided with a plurality of interface units, a plurality of interface units are the interface unit to different truck scale instrument agreement respectively. Carry out the dilatation through the interface arrangement to discernment interface system weighs, this interface arrangement is provided with a plurality of interface units, a plurality of interface units are the interface unit to different truck scale instrument agreements respectively, like this, have improved discernment interface system weighs's commonality for its truck scale that can use with different protocol interface is favorable to purchase, upgrading and the maintenance use etc. Of truck scale system product.