Before You Buy
Will I need to plug in power to this serial card from my power supply?
Serial cards derive power from the PCI or PCI Express slot on the motherboard. When you power serial devices from the serial card ports, the power provided by the slot may not be enough to power all of the devices and you should connect additional sources of power from the power supply. When you troubleshoot issues, you should connect an additional source of power.
Some signs that you are experiencing power-related issues include certain devices not working correctly, not all of the devices working at the same time, and certain devices not working at all.