Solution:

It is impossible to change the configuration from addressable mode to non-addressable mode without RS485 port. The command for the ADAM-4521 configuration is %AANNTTCCFFPP(CR). AA is the original address, NN is the new address. TT is the type code. Because the type code of the ADAM-4521 is only one kind, you can use the $AA2 to know the type code first. it should be "40". CC, FF, PP are the 8-bit parameters like the following listed. (CC) bit 7,6,5,4:232 BUAD RATE CODE bit 3,2,1,0:485 BUAD RATE CODE 0011: 1200 0100: 2400 0101: 4800 0110: 9600 0111: 19.2K 1000: 38.4K 1001: 57.6K 1010:115.2K (FF) bit 7: 0:ADDRESS 1:DUMB bit 6: CHECKSUM 0:DISABLE 1:ENABLE bit 5: 0:422 1:485 bit 4,3,2,1: Reserved bit 0: APPEND CR FLAG (PP) (For RS-232 only) bit 7,6,5: Reserved bit 4: 0:ODD 1:EVEN bit 3: 0:no parity 1:have parity bit 2: Stop bit bit 1,0: 00:5 bits 01:6 bits 10:7 bits 11:8 bits