Add two high speed esd protected rs232 ports with 5v or 12v selectable power output through a pci express slot the pex2s553s 2 port pci express serial card lets you add twoesd protected rs232 ports with 5v or 12v selectable power output through a pci express slot ideal for industrial environments this 2 port serial card offers built in 15kv esd protection which helps prevent damage to connected devices in the event of line surges and electro static discharge an extended operating tempe