Serial communication is one of data communication means, safer and cheaper than parallel communication in distant communication. It has been widely used in computer and device communication since the dawn of computer spread.
Almost all facilities in industrial sites and manufacturing equipments in factories use serial communication as their default communication means.
PC only has one or two serial ports, thus the need for more PCs arises when connecting a number of devices to the PC. However, this method is neither cost-effective nor rational. PCs in general consist of an optional slot for such extension needs. There are many types of slots such as ISA/PCI BUS, USB, IEEE 1394, and still others. A serial “Multiport” mounts multiple serial ports on one board or one box, enabling installation on a PC option slot.

PCMCIA is an organization consisting of some 500 companies that has developed a standard for small, credit card sized devices called PC Cards. Originally designed for adding memory to portable computers, the PCMCIA standard has been expanded several times and is now suitable for many types of devices.Multi-1A is a serial port PCMCIA card for the notebook computer. By connecting one asynchronous device like a terminal, modem, printer, or scanner, the PCMCIA Multi-1A makes the notebook more economical and powerful as the multi-device system. Transmission speed rises up to 921.6Kbps.

• 1 port per board
• RS232, RS422, and RS485 Serial Interfaces
• Serial communication speed of up to 921.6Kbps
• PCMCIA 2.0/2.1 and PC Card Standard compliant
• 16-byte FIFO and device driver control for RS422/485
• auto toggling
• Built in 15KV ESD
• Windows 2003/XP/2000/98/ME, Linux, and Unix driver support