It all depends on the distance between the call station and the monitor.
| Distance between the call station and the monitor | Cable to be used |
| Less than 80 m | 2 wires, 0.5 mm² minimum |
| Between 80 and 120 m | 2 wires 0.75 mm² min., 1.5mm² max. |
We do not recommend using telephone cable, as the diameter is too small, and it may cause malfunctions.