How a boundary wire works
Traditional robot mowers use a low-voltage wire installed around the lawn and connected to a charging station or transmitter. The mower detects the electromagnetic signal and uses it to recognize the edge of its permitted area.
Advantages
Once installed correctly, a wire can provide a predictable physical reference that does not depend on satellite reception or visible scene features. This can still be attractive on difficult properties with heavy tree cover or narrow strips.
Disadvantages
Installation takes time, changes require moving the wire, and accidental breaks can stop operation until the fault is found. Complex islands, paths and garden redesigns can also make the installation more involved.
Wire versus wire-free
Wire-free systems are easier to reconfigure and can offer more advanced mapping, but they depend on reliable localization. A boundary-wire mower is not automatically outdated if its operating environment strongly favours a physical reference.
Buyer takeaway
Choose based on the property and the amount of setup flexibility you need, not simply on which technology is newer.