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Diamond Systems EMM-OPT4-XT

PC/104 Module with 4 Opto-Isolated Serial RS-232/422/485 Ports and GPIO

Things Embedded are an official Diamond Systems UK distributor and can supply the EMERALD-MM-OPTO.


Serial I/O


Diamond Systems


Emerald-MM-Opto provides an integrated, rugged, and reliable solution for PC/104-expandable embedded systems requiring serial communications in demanding applications. It offers 2 or 4 optically isolated serial ports with RS-232, RS-422, and RS-485 protocols, as well as 24 digital I/O lines, all on a single board.

Optical isolation of 1000V DC or AC protects your embedded system from ground differentials or noise spikes that would damage non-isolated boards. Each port is isolated from the other ports as well as the system. Extended temperature capability (-40 to +85ºC) enables the board to operate in vehicles such as trains and buses without concern for temperature swings. These features enable Emerald-MM-Opto to provide reliable serial communications in harsh environments such as trains and buses.

In addition to ruggedness, Emerald-MM-Opto from Diamond Systems offers flexibility and advanced features. Each serial port is independently configurable for protocol and IRQ settings. Eight different I/O address combinations are built in. The 16C2850 UART chips with 128-byte FIFOs support high-speed data rates at up to 460kbps without overloading the system processor. Auto-flow control enables easy RS-485 operation by automatically enabling and disabling the transmitter during data transmission, to prevent bus conflicts or excessive software overhead.

Diamond Systems’ Emerald-MM-Opto also offers multiple termination methods on the serial ports to support varying interface requirements. In RS-422 or RS-485 networks, termination resistors are normally installed at the endpoints of the cables to minimize reflections on the lines. The board provides jumper-selectable termination and pull-up/pull-down resistors for this purpose. The sensible jumper positioning and layout help simplify board configuration and minimize confusion.

The 24 digital I/O lines are based on an 82C55 chip and feature programmable direction in 4- and 8-bit groups. All I/O lines contain user-configurable 10K Ohm pull-up resistors for convenience. This 2-in-1 combination of serial ports and digital I/O can help lower the size and cost of your embedded system by eliminating one additional board from your PC/104 stack.

Diamond Systems offers appropriate mating cables for your convenience. Cable no. C-DB9M-1 provides a DB-9 male connector with standard PC serial port pinout. Each serial port requires one cable. Cable no. C-26-18 is a 26-conductor ribbon cable for the digital I/O lines.


Brand & Model Diamond Systems EMM-OPT4-XT
PC/104 Module with 4 Opto-Isolated Serial RS-232/422/485 Ports and GPIO
Features Compact
Serial Ports 2 or 4, RS-232/422/485
Data Rates RS-232, 230.4kbps max
RS-422/485: 460.8kbps max
Signals RS-232: RXD, TXD, RTS, CTS
RS-422/485: RXD, TXD
Addresses 8 preconfigured standard I/O address options; custom addresses available
Interrupts IRQ levels 2, 3, 4, 5, 6, 7, 10, 12, 15;
Interrupt sharing supported
Isolation 1000V AC or DC, port to port or port to system
Termination 150Ω with 1KΩ pull-up/pull-down
UART 16C2850 with 128-byte FIFO and auto-flow control
Digital I/O 24 programmable direction using 82C55
DIO termination 10KΩ pull-up
Connectors Individual 10-pin connector for each serial port; 26-pin connector for digital I/O
Bus PC/104 16-bit bus (8-bit data)
Power +5VDC @ 300mA typical, all outputs open
Operating Temperature -40ºC to +85ºC
Dimensions 3.550″W x 3.775″H
RoHS Compliant

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