JMRI Hardware Guide: Connecting a LocoBuffer to LocoNet®
John Jabour designed the LocoBuffer as a reliable way of connecting a computer to a LocoNet®. He's no longer making them, but Hans deLoof has taken over for people who want to build their own.
The LocoBuffer II is currently the most reliable commercially-available way to connect a computer to a LocoNet. It is produced by Dick Bronson's RR-CirKits company, based in part on the original LocoBuffer design.
The recommended setup for the LocoBuffer is:
- The LocoBuffer should be configured with J1, J4 and J5 set on pins 1 and 2, J2 and J3 set to pins 2 and 3. This configures it for a 19,200 baud connection, with echo on.
Start DecoderPro or other program and configure it for:
- LocoNet LocoBuffer
- Select your port
- 19,200 baud
- Hardware flow control
For the most reliable operation, turn on your layout and computer before you turn on the LocoBuffer.
Some computers can successfully communicate at 57,600bps with a LocoBuffer. To do this, select "57,600 baud" when configuring and configure your LocoBuffer with J4 and J5 set on pins 1 and 2, J1, J2 and J3 set to pins 2 and 3 (J1 is the one that determines the baud rate). But we strongly recommend that you try 19,200 and make sure that works first.
The LocoBuffer controller chip should contain version 1.4.6 or later of the LocoBuffer program. Note that LocoBuffer version 1.4.5 has a bug that prevents it from working with this program. If you got your LocoBuffer chip after February 2002, this should not be a problem for you.
Some Windows versions, in particular Win2000, cannot handle the LocoBuffer's control leads properly. You'll see this as DecoderPro or PanelPro being unable to communicate with the command station, even though you can see LocoNet traffic with the LocoNet monitor. To fix this, try opening the preferences and select "no flow control" option, click save, then quit and restart the program. Note that this problem is specific to certain Windows versions, and you generally should have "hardware flow control" selected.
If the problem persists, please try jumpering-together the pins 5, 6 and 8 on the LocoBuffer's 25-pin connector. These are the CTS, DSR, and DCD leads in the LocoBuffers RS232 interface, and connecting them will (perhaps) fool your computer into accepting the LocoBuffers flow control signals.
That connector has a row of 12 pins and a row of 13. Looking at the solder-side of the board, pin 1 is at the end of the row of 13 (toward the center of the board), at the end nearest the RJ12 LocoNet jack. Next to that are pins 2, 3, 4 and 5 with traces on them. Pin 6 is next to that, with nothing connected. Pin 7 (ground) has a trace, then pin 8 does not.
So the suggestion is to connect pin 5 (with a trace) to pin 6 and 8 (without traces). Be careful not to short to pin 7, which is already connected.
LocoNet® is a registered trademark of Digitrax, Inc.