General
Number of ports	4
Data bits	5, 6, 7, 8
Stop bits	1, 1.5, 2
Maximum number of boards per PC	8

The Moxa CA-134I is a 4-port RS-422/485 PC/104 module, specifically developed for industrial communication applications where reliability, EMI protection, and high performance are paramount. The module integrates into embedded systems and provides a robust interface for serial data transmission in harsh environments. It is designed for use in systems with PC/104 bus and enables connection with CPU boards supporting this standard. The serial ports are designed for operation with RS-422 and RS-485 (in 2-wire and 4-wire configuration), with the RS-485 interface also suitable for multi-point networks. Optical isolation with 2 kV on all ports ensures high operational safety and protects against disturbances caused by electrical voltage spikes or potential differences. Integrated status LEDs for transmit (Tx) and receive (Rx) on each port facilitate diagnosis and fault detection during operation.

Applications

The CA-134I is used in applications within power supply, transportation, machine control, and remote monitoring systems. Its robust construction and support for wide temperature range (–40 to 85 °C) make it suitable for operating conditions in industrial environments with extreme temperatures. The module architecture is designed for use in compact, embedded systems where space and reliability are critical.

Functions and Features in Detail

The module features four serial ports configurable via DIP switches. I/O base address, interrupt (IRQ), and interface type (RS-422 or RS-485) can be set. IRQs are limited to channels 3–7, 9–12, and 15 (shared). The maximum number of installable CA-134I modules per PC is eight. Baud rate can be set from 50 bps to 921.6 kbps, including non-standard values. Data transmission occurs with 5, 6, 7, or 8 data bits, 1, 1.5, or 2 stop bits, and parity types such as None, Even, Odd, Space, or Mark. Flow control can be selected between None and XON/XOFF. Each port features a FIFO buffer with 64-byte capacity, enhancing data transmission efficiency.

Technology Explained Simply

Optical isolation with 2 kV protects the module’s internal circuits from electrical disturbances caused by differing ground potentials or inductive voltage surges. This is particularly important in industrial facilities where high electrical loads and interference sources are common. PC/104 compatibility enables modular expansion of embedded systems, with the module connected via a 40-pin box header. Integrated Tx/Rx LEDs provide visual indication of communication activity and simplify troubleshooting. Support for non-standard baud rates increases flexibility when integrating into existing systems.

Compatibility and Accessories

The CA-134I is compatible with common operating systems such as Windows CE 5.0/6.0, Windows XP Embedded, Windows 10, Linux (kernel 2.4.x, 2.6.x), and UNIX systems including FreeBSD, QNX 4, SCO UNIX, and OpenServer. Optional DB9 and DB25 connector cables are available, enabling connection to standard connectors.

Mounting and Installation

Installation is performed by inserting the module into a PC/104 system, connecting it to the main board via the 40-pin box header. Configuration is done via DIP switches, which determine the I/O address, IRQ, and interface type. No special tools are required, as the module is mechanically inserted into the system. Configuration is performed software-side after physical installation.

Operational Advantages

The combination of high isolation performance, wide temperature tolerance, and support for multiple operating systems makes the CA-134I a reliable solution for industrial communication tasks. Integrated diagnostic LEDs and flexible configuration via DIP switches simplify commissioning and maintenance. Support for non-standard baud rates increases compatibility with existing systems. The maximum of eight modules per PC enables scalable expansion of serial interface capacity.