The PCIe-ICM Series are a new family of isolated PCI Express serial communication cards. These PCI Express cards feature a selection of 4-ports of isolated, software selectable, RS-232, RS-422, and RS-485 serial protocols. 2kV isolation is provided between channels and between the PC and bus lines on ALL signals. The cards feature a x1 lane PCI Express connector which can be used in any available x1, x2, x4, x8, x12, or x16 PCI Express expansion slot. Each RS-232 port is capable of supporting data communication rates up to 921.6 kbps and implement full modem control signals to ensure compatibility with a broad variety of serial devices. RS-422 and RS-485 modes support data communication speeds up to 3 Mbps. Existing serial peripherals can connect directly to industry standard DB9M connectors which are provided on-board each card. The PCIe-ICM cards were designed using type 16C950 UARTS and use 128-byte transmit/receive FIFO buffers to decrease CPU loading and protect against lost data in multitasking systems. New systems can continue to use legacy serial peripherals, yet benefit from the use of the high performance PCI Express bus. The cards are fully software compatible with current PCI 16550 type UART applications and allow for users to maintain backward compatibility. The PCIe-ICM Series is especially useful in applications where high common-mode external voltages are present. Isolation is required to guard electronics from transient voltage spikes and offers greater common-mode noise rejection in electrically noisy surroundings containing industrial machinery and inductive loads. These applications include factory automation, energy management, military/mission-critical, industrial ON/OFF control, security systems, manufacturing test, process monitoring, and kiosks. In addition to protecting industrial applications from accidental contact with high external voltages, the isolation provided eliminates troublesome ground loops. Available accessories include a broad range of cables, screw terminal boards and breakout connection boxes for a variety of quick and easy connectivity options.