A simple RJ45 cross-over Ethernet cable can help you auto-check that your MVI56-MCM, MVI69-MCM, MVI56E-MCM, or MVI69E-MBS works well when troubleshooting your RS485 network.
The RJ45 cross-over Ethernet cable allows you to interconnect the two ports of your module to check for communication with one port as a master and the second as a slave.
This allows you to prove the module itself is working well and to focus on your network cabling, saving a lot of troubleshooting time.