Are you using the package PG radio or the OEM module?
RS485 can be tricky because there often isn't a way to test that the data is indeed coming from the receiver radio correctly. When using the X24-019 radios, the best indication that the module is properly wired are the LEDs on the package radio.
Each radio will come with a default baud rate, in your case the -019 of the part number indicates a default baud rate of 19200bps. The data format will default to 8N1.
At this point, the package radio needs to be set with the proper DIP switch settings. These can control RS232/485, 485 2 or 4 wire, parity settings etc. If these are set correctly, you must make sure to properly wire your RS485 2 or 4 wire system to the radio. You should refer to the product manual for proper pin connections to the radio.
Once the radio is properly wired and configured, you can then check communication by looking at the LEDs on the radio when you try and communicate. When the radio tries to transmit, the green LED will flash, when the other radio receives, the yellow LED will flash. If you do not see this happen, then it is an indication that your radios are wired incorrectly.
If you see the LEDs flash accordingly, and you still have no communication, most likely you have a timing issue, or a data format issue.