Ethernet Router Unit (ERU)

Ethernet Router Unit (ERU)

EKE Trainnet® ERU Front EKE Trainnet® ERU Side


EN 50155
EN 45545
IEC 61375-2-5
IEC 61375-3-4

Dimensions (W x H x D):
16 TE x 3 U x 160 mm
500 g
Input Power:
5 V DC ± 5 % (1.5 A typ. 3 A max.)
Temperature Range (operational):
-40 °C…+70 °C
MTBF (40 ºC ambient temperature):
450 000 h
Ethernet Interfaces:
4 x 10/100 Mbit/s M12 for ETB
6 x 10/100 Mbit/s M12 for ECN 
Serial Interface:
1 RS 232 on front
(for maintenance, configuration or ESN dongle)
Switching Buffer Memory:
2 Mbit
Management CPU:
PowerPC 667 MHz
Flash Memory:
512 MB
256 MB

module functions

The Trainnet® Ethernet Router Unit (ERU) is a combination of high performance Ethernet router and switch. It is used as an Ethernet Train Backbone node (ETBN) to create integrated Ethernet Train Backbone (ETB) and Ethernet Consist Networks (ECN). It provides connectivity for devices with an Ethernet connection and can complement or replace the Wire Train Bus (WTB).

The Trainnet® ERU module implements the ETB link layer function of the IEC 61375-2-5 as well as the ECN link layer function of the IEC 61375-3-4 Train Communication Network Standards. The Ethernet technology's large bandwidth (typically 100 Mb/s) is particularly suitable for data intensive systems like video surveillance or Passenger Information Systems.

key features

The Trainnet® ERU module routes traffic between the ETB and the ECN. 4 ports are dedicated to the ETB (2 separate lines in each direction of the vehicle) and 6 to the ECN. The bypassing functionality allows the information from the ETB to go through even if the car is unpowered. The Trainnet® ERU's non-blocking (QoS Layer 2) switching architecture provides large bandwidth: its 10 ports are 10/100BASE-TX Mbit/s Full Duplex Ethernet with auto MDI/MDIX M12 connectors. The Ethernet ports are located on the front panel of the module and communication to the gateway is done via one of the Ethernet ports. An Electronic Serial Number (ESN) port is available for device identification and configuration.

The ERU's ECN ports can be partitioned to create distinct ECN subnets using a virtual router. The possibility of using link aggregation provides an opportunity to increase data transfer capabilities as well to create redundancies.

The Trainnet® ERU module automatically handles the train inauguration as consists are connected to and disconnected from the train set. There is support for dynamically connecting up to 63 train backbone nodes. The module also has a DDNS server (i.e. Dynamic DNS server), so that end devices in vehicles can connect to each other through their domain names, not only the IP addresses. The ERU provides the train topology information to applications in a train directory.

Port mirroring can be used to copy packet data seen on a switch port to another port for diagnostic and monitoring purposes.

The ERU module's ECN switch provides connectivity to the consist network switches in a ring configuration (allows redundancy), or by connecting ports directly to end devices. The switch provides services such as Dynamic Host Configuration Protocol (DHCP) in order to assign IP addresses to end devices automatically. The management processor also provides VLAN configurations and Layer 3 switching. It enables diagnostic functions such as the identification of faulty cables.

technical specifications

The features of the ERU module also include: Firewall, Rapid Spanning Tree Protocol (RSTP), Virtual LANs, routing multicasts in ECN and ETB networks (IGMP based multicast forwarding), Train Topology Discovery Protocol (TTDP), Port based VLAN configuration, rate limiting, port monitoring, port RMON statistics counters, PHY configuration and process data export.

Published on: 2020-08-18

EKE-Electronics Ltd
Piispanmäentie 5
02240 Espoo
Tel +358 9 6130 30