USB-303 linear encoder exchanging box is the latest equipment for reading and exchanging linear encoder data. It has an isolated 3-axis linear encoder interface with 24-bit reversible counter to supply the users with the interface functions for the secondary development. In it a set of external signal trigger can lock the value of any 1-axis or 3-axis simultaneously with a value less than 20us. The polarity of RI signal A and B signal can be chosen when searching RI point with adjustable computation direction computation direction (+or-). It enhances the anti-jamming capability with external power supply for increased stability. Its plug and play option allows secondary development personnel can read the linear encoder data on the PC via USB port. It is used in applications like Manual video measuring machine (CMM, 3D VMM), X and Y working table monitor, Length Measuring Machine and suited for movement control and position measuring.