Gigabit Data Diode fibre in, fibre out


  • Guaranteed one way transmission
  • 1Gbps wirespeed throughput
  • Totally hardware based
  • Independent power supplies for both High and Low side.
  • Tamper proof casing
  • No vulnerable software, firmware, memory or buffers that may otherwise be exploited.



Security at its heart

Guaranteed to ensure data can physically flow in one direction only

Unidirectional data diodes provide defence against a broad range of external, cross domain and insider cyber threats that traditional security appliances are just not capable of dealing with. Data diodes stand guard between domains where unrestricted two- way communications increase the risk of penetration, malicious attack and data loss

Diode diagram

The GF-55SD is a Gigabit Ethernet data diode that ensures one way data transmission. A totally hardware based solution, the GF-xxSD is a Layer 1 device with fibre optic interfaces on both the high and low sides. The GF-xxSD operates at full 1Gbps wire speed for optimal performance. Desktop or rack-mountable the GF-55SD takes data security to new levels.

Careful consideration has been given to preventing any form of side channels being introduced. Independent circuitry for high and low sides are each powered by dual power supplies to provide both separation and resilience. All casings are tamper proof and EMI/RF screened.

Protection of Critical Infrastructure

  • Oil and Gas
  • Power Generation, Transmission & Distribution
  • Water & Wastewater
  • Financial Services
  • Transport - Road, Rail and Sea

Data diodes provide protection for these networks. By allowing exfiltration of data from a wide range of devices whilst protecting those devices from outside attack.

Data Diode SCADA

Protection of senstive information

  • Central and Local Government
  • Healthcare
  • Financial Services
  • Military & National Security
  • Commercial Enterprise

Data diodes protect sensitive information by enabling data to be submitted to a network (eg Patient records, Tax receipts, intellectual property, etc) but not allowing an outflow of data in the opposing direction.

Tx Data diode


Technical Notes

Configuring ARP for use across Data Diodes

Address Resolution Protocol (ARP) is a protocol used to ascertain the hardware address or Media Access Control (MAC) address from an IP address. Typically a sending station knows the destination IP that they wish to send to but does not the MAC address.  Before communication between the 2 hosts can occur an ARP request is sent to discover the destination MAC address.  The ARP request is directed to the destination IP address using a MAC broadcast address FF:FF:FF:FF:FF:FF.  All devices on the subnet receive this broadcast but only the destination with the correct IP address will respond.

Why do I need a data diode ?

Data diodes play an integral part in securing the most critical business assets, protecting the most valuable data and ensuring operational continuity.

The physical nature of a data diode ensures data can only ever flow in one direction. Typically they are deployed at the boundary between a high security environment and a lesser network, data diodes stand guard at this intersection where unrestricted two-way communications would otherwise increase the risk of malicious attack and data loss.

What is a data diode?

Data diodes are unidirectional data devices that prevent any unauthorised conversations taking place. Simply put - 'A data diode is a cybersecurity device that ensures data can only flow in one direction'


Item Description

IEEE 802.3u



1000 Mbps


Twin 100 ~ 240 VAC Auto-ranging wall-mount;
Twin 9 - 48 VDC input plus Terminal Block option


Operating: 0° to 50°C

Storage: -20° to 70°C


Operating:  10% to 80% RH

Storage:  5% to 90% RH


FCC Part 15 of Class B


US21 CFR (J)

EN 60825-1

UL 1950

EN 60950: Pending


(D x W x H)  127mm x 203mm  x 44mm



Ordering Information

Order Code Description
GF-55SD 2 x 1000BASE-SX (Multi-mode) Local User ports

More Information

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