A remote station cannot be reached by network cable. How do we add Wi-Fi or 4G/5G to an industrial computer reliably?

Whether wireless connectivity on an industrial machine is stable depends mostly on the antenna and installation, rarely on the module. Module slots: check for an M.2 B-key or mini PCIe slot for 4G/5G, an M.2 E-key slot for Wi-Fi, and whether there is a SIM tray. 5G modules run noticeably hotter than 4G, so a small fanless machine needs a thermal path for the module. Antennas: a metal cabinet blocks signals almost completely. Bring the antennas outside through extension cable and waterproof bulkhead connectors; longer cable means more loss, so place the machine close to the antenna position. For 4G/5G use two-path MIMO antennas. Stability: 1. Measure actual signal strength at the installation site before choosing a carrier. 2. Enable automatic reconnection and a connection watchdog. 3. The software should buffer data during signal loss. 4. Use a VPN for remote access instead of exposing ports directly to the Internet.