App note: RS-485 communication link vs. the electric fence, A demonstration of RS-485 EMC robustness

Analog Devices’ RS-485 robustness demonstration by direct application of HV transient to the communication line. Link here

Industrial and instrumentation applications (I&I) require transmission of data between multiple systems, often over very long distances. The RS-485 bus standard is one of the most widely used physical layer bus designs in I&I applications. Applications for RS-485 include process control networks, industrial automation, remote terminals, and building automation such as heating, ventilation, air conditioning (HVAC), security systems, motor control, and motion control.

In these real systems, lightning strikes, power source fluctuations, inductive switching, and electrostatic discharge can cause damage to communications ports by generating large transient voltages. Designers must ensure that equipment does not just work in ideal conditions but also works in the ‘real world.’

from Dangerous Prototypes