Digitrax UP3

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Summary: The UP3 was an early utility panel used to connect throttles to LocoNet. Discontinued in 2005 when the UP5 replaced it.


The Universal Panel 3 provides two Loconet jacks and track power connections on the rear, with two throttle connections and a track power indicator on the front. It lacks the LocoNet jack on the side. A maximum of 10 panels can be powered from a PS14 power supply using the provided jack. Additional panels may not work correctly without the addition of another power supply. A PS14 also powers the battery saver circuit.


  • Simple hookup, maintenance & troubleshooting of LocoNet.
  • Use with 6 conductor telephone cable with RJ12 6 pin connectors and Daisy Chain your LocoNet Ports around the layout.
  • "Battery Saver" Circuitry Built in (External Power Supply is required for battery saver)
    • This prevents wireless throttles from draining their battery when the layout is off.

Supplied with Digitrax Starter Sets

These sets and the UP3 have been discontinued.

Track Power Issues

If the UP3 was connected to track power, there existed a possibility of a failure.

The RJ jacks could have short circuit develop within them if throttle connections were pulled toward the sides during operation. This would result in erratic LocoNet operation. The cause was steering diodes providing power to the throttle which also isolated track power from LocoNet. This was also a problem if the track segment was powered with Direct Current.

The UP5 corrected this issue.

It is possible to protect the UP3 from damage by adding a 22Ω, 3W resistor to each track input. See UP3 Diode Protection

Usage with NCE Cab Bus

It was possible to use a UP3 with NCE's Cab Bus. The UP5 and UP7 have design changes that prevent their use with other throttle networks.

Instruction Manual

Available from Digitrax:

Digitrax Utility Panels