HEMSA-T-005 is a PCI to 4-port RS-232 serial port card, with a fast transient suppression protector designed to protect the RS-232 interface. This product can convert single-ended PCI signals into RS-232 signals. It adopts today's advanced TVS tube. Under normal circumstances, the TVS tube is in a high group state. When the two ends of the TVS tube are subjected to an instantaneous high-energy impact, it can reduce the impedance at both ends at a very high speed and absorb a large current, thereby clamping the voltage at both ends to a predetermined value to protect the following circuit components from being damaged by transient high voltage shocks. This protector can effectively suppress lightning and ESD, and provide TX/RX 600W lightning and surge protection, and also the protection to the surge and transient over-voltage generated on the wire for various reasons. The extremely small inter-electrode capacitance ensures the high-speed transmission of RS-232.