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USB-IIRO4-2SM - USB Isolated I/O and Serial Communication Board, 4 Iso In/Rel Out, STB, 2 RS-232/422/485 ports

Acces I/O



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Product Datasheet

This product is RoHS-compliant

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The USB-IIRO4-2SM is a USB multifunction device, incorporating a USB 4-port hub internally to provide four optically isolated digital inputs, four electromechanical relay outputs and two ports of RS-232/422/485 serial communication in one small product. The digital portion is ideal for adding easy-to-install isolated input and relay output capabilities to any PC or embedded system with a USB port. This single USB multifunction device is ideal for a variety of applications such as industrial monitoring, control and communication.


The isolated, non-polarized inputs may be driven by either DC sources of 3-31 V (or higher by special order) or AC sources at frequencies of 40Hz to 10kHz. Optically isolating the digital inputs from each other, and from the computer, assures smooth, error-free data transmission in noisy, real-world environments. The relay outputs are de-energized at power-up to prevent an unintended control output signal. Data to the relays is latched. The relay contacts and isolated inputs are available via a mounted DB25 connector or, for OEMs, a 26-pin IDC type vertical keyed shrouded header. For testing purposes and low current applications 5VDC and ground pins are provided on the same connector. The digital portion of the USB-IIRO4-2SM is excellent in applications where only a few on-board relays are required and a small number of inputs must be isolated such as in test equipment, instrumentation and process control.


The serial section is a two-port asynchronous serial communication adapter designed for use with any computer system equipped with a USB port. Multiple peripherals such as POS, barcode scanners, scales, date-entry terminals, data acquisition modules, and automation equipment can now be recognized and used on a single USB port. Simply install the included software and connect the unit to your USB port. It instantly provides two RS-232, RS-422, or RS-485 serial ports which can be selected on a port by port basis. It is now easier than ever to add serial ports and serial devices to any application along with easy plug-and-play and hot-swapping features.

Type FT232 UARTs are used as asynchronous communication elements. This includes 384-byte receive / 128-byte transmit FIFO buffers for high data throughput and to protect against lost data in multitasking systems. Crystal oscillators located on the card permit precise baud rate capability up to 230.4K for use in RS-232 mode, using ICL3243 type drivers. Speeds up to 921.6K are achievable using RS-422 & RS-485. The driver/receivers used are type SP491 which are capable of driving long communication lines at high baud rates. They can drive up to ±60 mA on balanced lines and receive inputs as low as 200 mV differential signal superimposed on common mode noise of +12V to -7V. In case of communication conflict, the driver/receivers feature thermal shutdown. The serial communications are conveniently provided through two DB9 board mounted male connectors with adjacent LEDs indicating serial port activity.


The USB-IIRO4-2SM includes a rugged steel enclosure with attractive powder coat finish and anti-skid bottom. The unit enclosure is 4 inches wide by 4 inches deep by 1.8 inches high. The adapter is supplied with a 6 foot USB cable. In addition to the two serial LEDs the unit features two additional easy-to-read LEDs indicating digital I/O enabled/ready and USB power. Port protocol is configured by opening the enclosure and configuring jumpers on the circuit board. It is fully compatible with both USB 1.1 and USB 2.0 ports. The OEM version provides just the board without the enclosure and is ideal for a variety of embedded OEM applications.