Tripp Lite's DB9 offers dataline surge suppression for DB9 serial ports of data terminal and data communications equipment, including PCs, printers, modems and more. User configurable for use with male or female captive DB9 ports. Offers protection on all 9 lines, plus D shell chassis. Convenient DB9 input and output connects directly to the protected port, obtaining a ground outlet from the computer chassis. Surge suppression is handled with balanced arrays of high-speed avalanche diodes that divert excess energies created by electrostatic discharges, faulty wiring or lightning away from network interface connections. Tripp Lite network surge suppressors reduce blown interface cards, garbled transmissions, system lock-ups and hard equipment failure by safely shunting dataline surges to ground. Lifetime warranty.SUPPRESSION: Reversible DB9 m/f jacks, protects pins 1-9 and chassis, 18V clamping