performance AX99100 chip enables reliable RS232 communications with up to 920.6 KBPS data transfer rate. Interface standard: RS232 standard port DB9pin (4/2 RS232 standard port). Expansion capability: can be expanded with 2 or 4 additional DB9 ports for connecting external devices. Slot compatibility: fits PCIe slots X1 and X16 of different lengths. Use scenarios Industrial automation and data collection: connect multiple RS232 devices such as PLCs, sensors, and other serial peripherals to a single PCIe host PC for centralized monitoring and data logging. Legacy equipment integration: provide serial console access and control for older equipment that relies on RS232 interfaces, enabling modern system management without replacing existing hardware. Development and testing: use as a flexible serial I/O expansion for prototype testing, debugging serial communications, and validating external device interfaces in a lab environment.