General
FIFO memory	128 Byte
Data bits	5, 6, 7, 8
Stop bits	1, 1.5, 2

The Moxa CB-108 is an 8-Port RS-232 PC/104-Plus module, designed for integration into embedded systems with a PCI-based PC/104-Plus interface. It enables serial communication with external devices and is specifically designed for industrial applications where reliable and data-intensive transmission is required. The module provides eight independent RS-232 interfaces, connected via a 40-pin box header. Communication occurs over the PCI-based PC/104-Plus bus, used in compact, modular systems.

Applications
The CB-108 is suitable for use in industrial control systems, automation systems, and data acquisition devices, where multiple serial devices need to be connected and monitored simultaneously. The wide-temperature version with an operating temperature range of -40 to 85 °C makes the module suitable for harsh environments such as production halls, outdoor installations, or mobile vehicles. The BIOS-configurable IRQ and I/O address allows flexible integration into existing systems without additional jumpers or manual settings.

Functions and Features in Detail
Each of the eight RS-232 ports features a 128-byte FIFO buffer, which enhances transmission efficiency and prevents data loss at high data rates. The maximum baud rate is 921.6 kbps, sufficient for data-intensive applications. The on-chip hardware and software flow control (RTS/CTS and XON/XOFF) ensures stable data transmission, especially when transmission speeds differ between sender and receiver. For visual monitoring of port activity, Tx/Rx status LEDs per port are integrated, directly indicating data traffic.

Technology Explained Simply
The RS-232 interface is a standard serial interface used for communication between computers and serial peripheral devices such as sensors, printers, or industrial controls. FIFO technology (First In, First Out) temporarily stores received or to-be-sent data to reduce CPU load and optimize data transmission. Flow control prevents the receiver from being overloaded by temporarily halting transmission when the receiver cannot process more data. BIOS-configurable address assignment eliminates the need for manual jumper settings, simplifying installation and reducing error sources.

Compatibility and Accessories
The module is compatible with a variety of operating systems, including Windows CE 5.0/6.0, XP Embedded, and Windows 10. Driver support covers all current Windows versions, enabling broad integration into existing system environments. The maintenance software Moxa Tools is included in the delivery scope and enables configuration and diagnostics of the interfaces.

Mounting and Installation
Mounting is done by installing the module into a PC/104-Plus system. The connection terminal is a 40-pin box header, directly connected to the mainboard. Configuration is performed via BIOS, where IRQ and I/O address are assigned automatically. The maximum number of installable CB-108 modules per system is eight, enabling scalability for larger applications. DIP switches are provided for selecting the interface type and are intended for individual customization of port functions.

Operational Advantages
The CB-108 offers high reliability through robust hardware and software flow control, as well as the large FIFO buffer. The integrated LED indicators simplify troubleshooting and diagnostics during operation. BIOS-configurable address assignment reduces installation time and minimizes configuration errors. The wide-temperature version ensures stable operation under extreme environmental conditions, which is critical for industrial applications. Compatibility with various operating systems and support via Moxa Tools increase the module’s flexibility and maintainability.