It consists of TVS Diodes (CDSOT23-SM712), TBU™ Devices (TBU-CA065-100-WH), and one or more GDTs. Each device contributes a unique protection function. Due to the layered protection scheme, the TVS array is fully protected by the TBU device and the TBU device is fully protected by the fast GDT. The limits of surge protection are then those of the GDT itself. The Bourns GDT for RS-485 Ports handles extremely high currents and coordinates with the TBU device to provide extremely fast voltage protection, as well as protection the TBU device from excessive voltage after it triggers.