LocoNet/Troubleshooting

== Troubleshooting LocoNet ==
Also see the Digitrax Hints page for a list of Audible Alerts
Troubleshooting LocoNet Connection Issues: 
# Disconnect all LocoNet connections, inspect the modular jack, and try one leg at a time to identify the affected section.
# Identifying Jack Issues: Swap A and B connections to determine if the jack is faulty.
# Resolving Network Issues: Disconnect devices on the affected section, reconnect them one at a time, and try different cables or bypass devices with longer cables if the issue persists.
=== Construction Issues ===
Many LocoNet problems aren’t actually LocoNet-related issues; they’re mechanical or electrical problems with the cabling.
==== Break in LocoNet Signal ====
One issue is that the LocoNet signal from the command station is only present on one of the two LocoNet (red and green) wires. Usually the command station provides the LocoNet signal on Pin 3 (the red wire). At some point a device, such as a throttle, will bridge pin 3 to pin 4.
Devices such as a throttle, the LNRP or a UP92 will provide this bridge. The DT400 is known for not bridging pins 3 and 4. Another culprit is the UP5. 
The LT5 LocoNet Tester can be used to determine if bridging is taking place, and then be used to find out where the bridging is occurring. It can also determine if the LocoNet signal is on the red wire before the bridge.
If a downstream booster stops responding, it’s possible that there’s a break in the wires carrying the LocoNet signal from the command station. If there’s a utility panel connected between the command station and the booster, and this issue only occurs when the throttle is unplugged, it indicates that one of those cables has a problem. Removing the throttle from the panel disconnects the bridge between wires three and four on the LocoNet cable. 
If there are multiple panels between the command station and the booster, any one of those panels can be used to connect the two LocoNet wires. By using a throttle, you can isolate the cables involved by testing each panel until the issue is identified.
If there’s no command station on the LocoNet, a LocoNet termination can also connect lines 3 and 4.
==== Crimping Issues ====
Improperly crimped connections are quite common. It’s crucial to use the appropriate type of connector and a high-quality crimping tool. 
There are two types of RJ connectors available on the market depending on the wire type:
* Solid Wire
* Stranded Wire
Using a solid wire RJ connector on a stranded wire might work, but it’s not reliable. If it were, there would only be one RJ connector for both types of wire. Using a connector designed for stranded wire to terminate a cable with solid conductors would cause problems because the two prongs penetrate the insulation, potentially causing the wire to break at that point. Nicks in solid wire weaken the wire at that location.
 Incorrectly crimped terminations may pass an LT1 test but fail with LocoNet devices. 
==== Troubleshooting a LocoNet Cable ====
Using a DMM, measure the voltages on the cable, referencing the Ground terminal on the command station.
* A healthy working LocoNet should have 10V or more available between ground and pins 3 or 4 of the RJ connector. 
* A cable with a poor, high resistance connection will see a reduced voltage on the pin(s).
* The voltage should be 9 to 10V on those pins.
==== RailSync ====
The RailSync wires (the outer pins of the RJ connector) can become an open circuit without causing any significant issues with the connected devices. RailSync is a low-voltage, low-power representation of the track signal. Your DMM can help identify the problem. Since these signals are not in phase, it’s crucial not to short them together.
=== Digitrax Zephyr Specific ===
With a DCS100 integrated command station/booster or DB150 booster, only one of the LocoNet wires (3 and 4) is driven. Connecting a throttle bridges them. 
In most LocoNet implementations, the two LocoNet wires are paired together. Throttles, DS54s, and the LocoBuffer all pair pins 3 and 4. 
In certain circumstances, this may not occur. If a LocoNet device fails to function, this could be the problem. A common culprit is the DCS series Zephyr when connected to LocoNet devices. The Zephyr internally connects the two wires using a resistor. Consequently, the devices malfunction because the signal is missing.
The solution involves a shorting plug made from an RJ connector. A wire connects pins 3 and 4, which is then crimped. Inserting the shorting plug into any available spare LocoNet jack resolves the issue.
=== LocoNet Termination Issues ===
LocoNet Termination for this discussion refers to the supply of power to the Rail Sync lines. If you are looking for terminations on a power bus, please refer to the Bus Termination page. 
Some devices may not function properly if the LocoNet is not terminated correctly. Many LocoNet devices rely on the RailSync wires for power. A low-current 12VDC source can provide this power for a standalone LocoNet. Another function of the termination device is connecting pins 3 and 4 together. For a standalone LocoNet implementation, a small 12V power supply is used to power the Railsync lines..
A number of devices, such as the PR3 can provide LocoNet termination.
A Utility Panel can also supply power on the Rail Sync lines.
=== Digitrax LT1 ===
===Rail Sync===
Low voltage RailSync signals are present on the cables. Check for them using the LT1. The two outer LEDs must be bright, and constantly lit. If not, work your way through the network until the offending cable is located.
For proper operation of the booster, all four LEDs should be lit.
:This is not the same as a booster phase issue.
===DCS100/DCS200 Command Stations===
The NET indicator on the DCS100/DCS200 Command Station is a Red LED that displays information about what the Command Station sees on LocoNet. When your LocoNet is wired and operating properly, the NET indicator will be on and flickers any time a valid LocoNet message is detected by the Command Station. The following table explains the various patterns for this indicator:
; Solid Red : OK
; ON, Blink OFF : Valid LocoNet Message detected.
; OFF: LocoNet is possibly shorted
; Blinking every half second: The command station is in Option Set mode.