Skip to main content

Diamond Systems MRC-424-XT

PC/104-Plus Module with Quad 10/100 Ethernet and Digital I/O

Things Embedded are an official Diamond Systems USA distributor and can supply the MERCATOR II.


Ethernet I/O


Diamond Systems


The Mercator II PC/104-Plus module integrates 4 PCI-based 10/100 Ethernet ports with 24 user-configurable digital I/O lines in the compact and rugged PC/104 format. This 2-in-1 combination of Ethernet 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.

The Ethernet ports are driven by two dual Micrel KSZ8842 Mac + Phy PCI controller chips, two ports per chip, and are NE2000 compatible. Each chip has a unique MAC address; therefore, only two Ethernet ports are visible to the end user for active communication. The other two ports work in switch fashion to enable daisy chaining of networks with one port on the chip as an uplink to a network while the other port provides active communication on the network.

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.

Extended temperature capability (-40ºC to +85ºC) enables the board to operate in environments with extreme temperature swings, such as vehicles or outdoor installations. In addition, the board may be custom-configured with 0-ohm resistors in place of jumper blocks for increased ruggedness in high-vibration environments.

Diamond Systems offers appropriate mating cables for your convenience. Cable number C-PRZ-02 provides a panel-mountable RJ-45 connector for the Ethernet, and cable number C-26-18 is a 26-conductor ribbon cable for the digital I/O.

Configuration Options

Several features are configurable using either a dual-row 2mm size jumper block or a switch. Provision is made on the board for zero-ohm resistors to replace jumpers to enable a hard-wired configuration.

  • Digital I/O base address (8 address options with 3 jumpers)
  • Digital I/O configuration: pull-up enabled or disabled
  • PCI slot selection for each Ethernet port


Brand & Model Diamond Systems MRC-424-XT
PC/104-Plus Module with Quad 10/100 Ethernet and Digital I/O
Features Compact
Number of Ethernet ports 4
Protocol IEEE 802.3 10Base-T and 100Base-TX compatible
Maximum data rate 100Mbps
Digital I/O
Number of I/O lines 24
Direction Programmable: Ports A and B individually programmable for all input or all output.
Port C programmable in 4-bit groups for input or output
Input voltage Low: -0.5V min, 0.8V max
High: 2.0V min, 5.5V max
Output voltage Low 0.0V min, 0.4V max
High 3.0V min, Vcc – 0.4V max
Output current 2.5mA max, each line
Pull-up resistors 10KΩ pull-up
I/O headers
    Ethernet ports 6-pin straight male headers
    Digital I/O 26-pin (2×13) .025″ square pin header on .1″ centers
Mating cables
    Ethernet ports Cable number C-PRZ-02
    Digital I/O Cable number C-26-18
Dimensions 3.55″ x 3.775″ (PC/104-Plus standard)
Power supply +5VDC 10%
Operating temperature -40ºC to +85ºC
Operating humidity 5% to 95% noncondensing
PC/104-Plus bus Both ISA and PCI stackthrough headers installed

Need Help Choosing Ethernet I/O?

Tell us about your application and a member of the team will get right back to you.