Solution:

ZZ-Nx-485 FAQ ZZ-Nx-485 Series Setup Fails (ZZ-NA-485) All of these units potentially have a problem if jumpered and TB plugged in. 1. Customer put jumpers between TDA- and RDA- and TDB+ and RDB+ and changed some settings, tried to update after changing baud rate. 2. Setup saving settings failed. Then he could not find the unit again or change the settings. This entire series has this as a potential problem. The terminal blocks for RS422/485 should not be plugged into the unit during setup, no device must be sending data to TB during setup. When using the RS232 connection for data, (not setup) the handshaking lines for RTS/CTS must not be held High, Enabled.