The Matrix in the Matrix: Standalone 12-port Router Card with 8,448 x 8,448 Inputs on Outputs

The XRT board is a super routing matrix for Base Devices that can switch and distribute signals independently. Six of the twelve SFP ports support high-speed connections, each of which can transmit 2,048 audio channels.

The XRT card is suitable for large NEXUS systems that require complex network topologies and very high channel counts. As is common in NEXUS networks, Base Devices are connected via duplex fiber optic cables; the XRT plug-in card has twelve standard SFP ports that can be equipped with modules for multimode or singlemode fibers as required.

All twelve available SFP ports transmit the familiar NEXUS protocol with 256 audio channels. Six of the ports can also be operated in high-speed mode and can then handle up to 2048 channels, which means that even the largest capacity requirements can be reliably met. If one of the lines is interrupted, the card automatically uses the second connection. As a special feature, the XRT card supports the use of SFP modules with RJ45 connectors, which enable Ethernet tunneling via the NEXUS network: A simple, helpful option to use the NEXUS infrastructure for otherwise separate Ethernet networks.

Tunneling of Ethernet

Two of the fiber ports can tunnel Ethernet between two XRT boards when equipped with appropriate SFP modules. More ports can be configured on request. The data rate can be up to 1,000 megabit/s.

Independent Routing Matrix of 8,448 x 8,448 Inputs and Outputs

The routing capacity has been designed in such a way that all channels of the fiber optic connections and those of the Base Device can be included.

Automatic Propagation Delay Compensation for Very Long Fiber Optic Connections

In a NEXUS network, large differences in the distances of the fiber optic connections can occur, among other things, so that the latency that occurs is detected and compensated for by analyzing the word clock phase position.

6 High-Speed Ports for the Transmission of 2,048 Audio Channels

Half of the available fiber ports are designed as high-speed versions and can transmit up to 2048 channels. Together with the routing function, this makes it possible to chain the Base Devices according to the daisy-chain principle.

Sample-Accurate Switching in Case of Failure of Redundant Connections

In both port-based redundancy and card redundancy, signal switching is not audible and can only be detected by a message in the operating software.

Exchangeable Standard SFP Modules

The ports of the XRT card can be equipped with interchangeable SFP fiber optic modules to meet different applications. The modules can be included in the delivery or fitted by the user. Multimodemodemodules are used as standard, which allow a transmission with a range of 500m. Alternatively, single-modem modules with a range of up to 100Km can also be used.

Redundant Configuration of Ports Possible

If two Base Devices are connected redundantly, the signals are sent over both lines, so that in the event of an accident the signals can be switched over with sample accuracy and without crackling.

Optionally Activatable Re-Routing in Case of Failure of Non-Redundant Connections

When optical rerouting is enabled and a fiber optic connection fails or is disconnected, the board automatically searches for another route to the destination. This happens with an interruption of the data stream.

Support of Any Network Topologies

The network topologies are freely selectable and, for example, a circular or star-shaped connection structure can be set up.


Largest Audio Networks with Multiple Star Networking

Star networking is a combination of NEXUS Base Devices with one or two redundant fiber optic lines to form a central Base Device that is equipped with an XRT module. Thanks to the integrated matrix with 8448 inputs and outputs, up to 12 other Base Devices with all 256 audio channels can be connected. But the six high-speed ports with a transmission capacity of 2048 channels allow the exchange of all possible audio data from eight Base Devices and thus the creation of complex network topologies with several star networks that are interconnected.

Daisy Chaining of Base Devices with a Very High Number of Channels

The routing function of the XRT card allows all channels of multiple NEXUS Base Devices to be looped through, previously limited by the capacity of the active backplane. The fiber optic card XFOC is in principle a pure I/O board, only with the proprietary Stage Tec protocol. If the nature of the NEXUS network structure requires daisy-chaining, i.e. the transfer of audio channels from one NEXUS Base Device to the next, a correspondingly large number of the 256 time slots available per NEXUS Base Device is always used. These minimize the maximum input and output channels of the respective Base Devices. Unlike the usual XFOC card, the XRT board has its own routing matrix, so that the channel capacity of forwarded audio channels from other Base Devices is not loaded.

Technical Specifications :


XRT_04 1 x 8TE
SFP 12x NEXUS-fiber optic protocol bidirectional

Technical specifications

Audio data

Audio channels 512 channels at 48 kHz using 1G connection
2048 channels at 48 kHz using 6G connection


Capacity 8448 sources to 8448 sinks; no routing-performance limitation when using redundant optical lines
Sample rates NEXUS system clock, 32...96 kHz

SFP high-speed ports

Ports 6 (ports 1...6)
Data rate 6.25 Gbps
Audio channels 2048 (max., bidirectional)
Data format new NEXUS high-speed optical protocol
Compatibility NEXUS low-speed optical protocol (up to 512 channels);NEXUS XFOC07 optical protocol (up to 256 channels)

SFP standard ports

Ports 6 (port 7...12)
Data rate 1.25 Gbps
Audio channels 512 (max., bidirectional)
Data format new NEXUS low-speed optical protocol
Compatibility NEXUS XFOC07 optical protocol (up to 256 channels)

Ethernet interface

Ports 2 (ports 11 and 12 can also be used for Ethernet tunneling)
Available data rate depends on the audio-data utilization of the optical links:
100 Mbps, 1G-NEXUS optical link, max. audio utilization;
1 Gbps, 1G-NEXUS optical link, no audio utilization;
1 Gbps, 6G-NEXUS optical link, max. audio utilization
Port modules optical modules or
10/100/1000 Base-T (copper) SFP modules on request

Operation conditions

Temperature range 0° C to +50° C
Max humidity max. 90 %, non-condensing

Storage conditions

Temperature range –35° C to +70° C
Max humidity max. 90 %, non-condensing

Power supply

Voltage +4,75…5,25 V
Currrent 2.6 (with 12 SFPs 10 km SM, 1G)

Mechanical data

Weight 1,01 kg
Downloads :

NEXUS / NEXUS Star Technical Specifications




XRT Technical Specifications