The VEX-144 card provides 4 non-isolated RS-422/RS-485 serial ports and the VEX-144i card provides 4 isolated RS-422/RS-485 serial ports which tolerate isolation voltage up to 2.5 kV. Each port can be configured as either RS-485 for half-duplex or RS-422 for full-duplex communication. It is equipped with a 128-byte hardware FIFO for each port, supports for speed up to 115200 bps and is capable of transmitting information over a long distance communication link.

Users may specify a COM port number manually by setting DIP switch, or let the driver choose an available number automatically. The driver provides a maximum of 128 KB software FIFO for each COM port under Windows. It's practical for large file transmission.

The data lines of each serial ports on i version VXC cards come with photocouplers design. The on-board photo couplers use a short optical transmission path to transfer a signal between elements of a circuit, and keep the data lines electrically isolated. It can help cutting down on ground loops, common mode voltages and block voltage spikes, provide electrical isolation, and offer significant protection from serious over-voltage conditions in one circuit affecting the other.

In harsh industrial environments, the on-board ESD protection component (for i version) diverts the potentially damaging charge away from sensitive circuit to protects the computer and equipment from the sudden and momentary electric current.

The serial communication card are designed for use with intelligent devices like bar code reader, serial printers, intelligent sensors, instrumentation equipment, computers and almost any device with an RS-232 port.