UM400a/UM450 v2.0

This version works with the new hardware design (both circuit boards changed) incorporating the National LMX2485 PLL. This version is also compatible with the newer 93LC86B EEPROM as well as the original 93LC86 EEPROM. Hardware using v1.x firmware must stay with v1.x firmware. Version 2.0 works on new hardware but is functionally identical to version 1.4.