Solution:

There are some simple way to test the ADAM-4521 with string command: 1, Use the command "$002" to get the current configuration. Normally you will get the response like "!0140660103" That means: ! -- response header 01 -- current address 40 -- always 40 66 -- 9600 baud rate on both 232 and 422 side 01 -- address mode, no checksum, 422, append CR 03 -- data type N, 8, 1 2, If you want to change the address, please connect the INIT* pin and issue the following command %000240660103 That will change the address into "2".