The PCI-xxM-1S isolated and non-isolated asynchronous serial communications cards for PCIbus computers support RS-422 and RS-485 balanced mode transmission/reception, and provide automatic control of RS-485 drivers for Windows systems. The PCI-ICM-1S 500V opto-isolated and PCI-COM-1S non-isolated cards provide on-card jumpers to increase the serial data rate from 115.2 kbps to 460.8 kbps. Buffered asynchronous communications elements prevent data loss in multitasking systems while providing 100% compatibility with the original IBM serial port. The cards fit into standard 5V PCI slots in any IBM compatible computer. Menu-driven sample programs and drivers for DOS, Visual BASIC, Windows 3.x/95/98/NT and LabVIEW and other utilities are provided on a single CD at no charge. Price is $235 for isolated and $179 for non-isolated cards with manual and software.