ORXJ-1 5port Xpressnet Junction

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ORXJ-1 is a 5port Xpressnet junction. It is designed for use with any Xpressnet device.

Introduction

This do-it-yourself (DIY) Xpressnet junction provides some features that may be useful. The best feature is that you only need to assemble the some RJ12 plugs to get a working Xpressnet junction. The other parts are optional.

Main features

  • 5 Xpressnet plugs
    • 3 plugs for e.g. throttles
    • 2 plugs for Xpressnet in and Xpressnet out, both plugs are connected with the DCC signal (optional) at pin 1 and 6. 12V input by Xpressnet in plug can be switched off by jumper if you want to use internal power supply or external 12V DC supply
  • optional build in 12V DC power supply, up to 30V AC input
  • optional 12V DC input
  • 2 optional DCC screw terminals
  • LED for 12V DC
  • LED for internal power supply
  • If you don't like or need all this stuff leave the parts out. The circuit works also with only 5 or less RJ12 plugs.
  • easy to etch 100 x 50 mm PCB, unfortunally some vias.

Block diagram

Files

Schematics and PCB artwork was created with KiCad, an Open Source (GPL) PCB Suite. Complete CAD files are accessible through RocRail Subversion repository.

Version 0.5:

Get the parts

The parts are available all over the world. To see the specs of the used parts click on the links below.

amountpart / link
56 port RJ12 modular jack
42 port screw terminal
2LED 3mm, 2mA
2Jumpers
2Diodes, 1N4001
2Resistors, 4k7
1Multi pin connector
1Rectifier B80C1500
1Elko, 1000µF, 35V
1Elko, 100µF, 16V
1Capacitor, 100nF
1Voltage regulator 7812

There is also a Reichelt shoping cart. But they deliver only to germany. Anyway, there is a real chance to get these parts at your local electronic dealer.

Building

Building is quite easy.

  • First assemble the small parts, Solder the via's, resistors and diodes.
  • After that insert the screw terminals, the rectifier and Elkos.
  • If this is done solder the rest.

If you use the internal power supply you have to use a heatsink for the 7812 regulator.

The heatsink has to be big enough to dissipate the heat from the 7812 depending on the power loss over the regulator.

An Example

You connect a 18V AC transformer and your xpressnet devices have a consumption of 500mA.

The power loss equals ((18V -0,7V) x 1,41 -12) x 0,5A = 6,1965 W

Check your pcb for shortcuts, especialy between the pins of the RJ12 jacks.

connect a 12V transformer and measure if the power supply works.

Read the chapter “usage” and test your pcb with Xpressnet devices.

The Heatsink is NOT GND, it is 0,7V above GND. If you don't like it you have to isolate the regulator from the cooler using plastic screws and glimmer

Usage

use with 12V over Xpressnet cable (e.g. from the command station)

  • close jumper JP2
  • connect an Xpressnet cable from the command station or the previous ORXJ-1 to Xpressnet jack J1, LED D5 will light, LED D3 is off (if assembled).
  • connect the next ORXJ-1 (if there is any) to Jack J2.
  • optional you can connect the DCC signal with one of the DCC screw terminals. It will be forwarded to the next ORXJ-1. You can connect stationary decoders to the other DCC screw terminal.
  • J3, J4 and J5 can be connected with Xpressnet throttles or other Xpressnet devices.
  • in this configuration there is no need to assemble the following parts: D1, D2, D3, D4, P1, C1, C2, C3, R2, JP1, P1, P3 and U1

use with external regulated 12V DC power supply

  • open jumper JP2
  • connect a regulated 12V DC power supply to the DC screw terminal P3. The square solder pad is +12V, the round one is gnd. LED D5 will light, LED D3 is off (if assembled).
  • connect an Xpressnet cable from the command station or the previous ORXJ-1 to Xpressnet jack J1.
  • connect the next ORXJ-1 (if there is any) to Jack J2.
  • optional you can connect the DCC signal with one of the DCC screw terminals. It will be forwarded to the next ORXJ-1. You can connect stationary decoders to the other DCC screw terminal.
  • J3, J4 and J5 can be connected with Xpressnet throttles or other Xpressnet devices.
  • in this configuration there is no need to assemble the following parts: D1, D2, D3, D4, P1, C1, C2, C3, R2, JP1, P1 and U1

use with external 12 to 24V AC transformer

  • open jumper JP2
  • close jumper JP1
  • connect a 12 to 24V transformer AC screw terminal P1. LED D5 and LED D3 will light.
  • connect an Xpressnet cable from the command station or the previous ORXJ-1 to Xpressnet jack J1.
  • connect the next ORXJ-1 (if there is any) to Jack J2.
  • optional you can connect the DCC signal with one of the DCC screw terminals. It will be forwarded to the next ORXJ-1. You can connect stationary decoders to the other DCC screw terminal.
  • J3, J4 and J5 can be connected with Xpressnet throttles or other Xpressnet devices.

What if it does not work?

If you have trouble building or using ORXJ-1 please write a post in the hardware section of the Rocrail forum.

Pictures

ORXJ-1 V0.5

ORXJ-1 V0.5

Disclaimer

This is Do It Yourself Hardware. If you burn down your house or have to call the doctor there is no one responsible than you ;-)


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