The cPCI-3544 is an enhanced four ports serial communication module for industry communication interface RS-422/485 by Compact-PCI platform. It includes a PGA (Programmable Gate Array) to support the serial communication controller and a 37-pin connector to connect external I/O port from the front panel or using the rear I/O. The expansion cable has four standard DB25 or DB9 connectors and one DB37 connector to connect with cPCI-3544 interface card. The cPCI-R3544 transition board can support rear I/O connection by using one DB37 connector.