Digitrax Wireless operation

In June, 2009, DIgitrax announced their long awaited Duplex radio system. In 2016 Digitrax stopped manufacturing the simplex radio cabs (R suffix) and the UR91 simplex base unit.

This raised a bunch of new questions. Mr. DCC will try to answer them for you here!

What is the difference between the old and the new system?

The Digitrax system that had been around for years used SIMPLEX operation - that is, the cabs transmitted their data to the base and had no confirmation of receipt of the data. The cabs only transmitted when they had data to pass along. You turned the dial to change loco speed and when you stopped turning the dial, the cab sent a new speed value to the base station who relayed it along the LocoNet to the command station. Since selecting a loco (acquiring and dispatching) requires an exchange of data, you could only do that when the cab was plugged in.

DUPLEX communication is bi-directional, with both the cab and the base station transmitting and receiving data. This allows you to select locos and perform all programming functions wirelessly! The new duplex radio is in the 2.4 GHz band, along with WiFi, BlueTooth, portable phones, etc. This band allows more data to flow between the cab and the base, providing more features and range and less interference. The new system should have a 50 yard (or meter) range between the cab and the base. With that extended range comes a lot more opportunity for interference between adjoining layouts, for example, at train shows. The added data capabilities, allow the addition of a GROUP NAME to the data being shared. Thus, Club A can have a different name than Club B, next door. Those units for A will only communicate between themselves, ignoring the B units, and vice versa.

Can we use both systems on the same layout?

Absolutely. They were designed that way, so as not to obsolete all the equipment you have installed. A UR91 simplex receiver and a UR92 duplex transceiver can be plugged into the same LocoNet system. The duplex cabs communicate through the UR92 and the (older) simplex cabs continue to communicate through the UR91.

Will the old cabs and receivers be supported?

They were from 2009 to 2016. Production ceased in 2016.

Our club already has the simplex system running, 
what do you recommend we do?

I suggest you budget about $130 for a UR92 to add to your layout in the future. This will allow for the future. Simplex cabs are no longer manufactured and eventually, only duplex cabs will be available.

However, many clubs report loss of control on their layouts with the current system. The duplex system will go a long way toward reducing that phenomenon. Adding a UR92 to your layout as soon as possible and upgrading the cabs will fix MANY of the issues clubs have. The old system got a little crazy when you had a lot of throttles active. The new system is designed to accommodate "dozens" of cabs at once.

How do all these items play together?

Perhaps the best way to explain this is with a chart! Reading across the chart, you can see what parts and items and sets work together.

Wireless Type Programming Throttle Utility Throttle Base Unit
IR (Infrared) DT402 UT4 UR90
Traditional (simplex) Radio DT402R UT4R UR91
New (Duplex) Radio DT402D UT4D UR92

The conversion of a simplex layout to duplex will be the subject of a future MRH column.


Can I upgrade my throttles and base units?

Yes and no. Digitrax can upgrade your throttles.
CLICK HERE for the Digitrax site information on throttle upgrades.

There is no "upgrade" for the UR91. Addition or substitution of a UR92 is the only way to add duplex operation to your layout. AND YOU MUST HAVE "D" series throttles to run wirelessly with it.

My country is not listed as a place where Digirax sells the radio system. 
What can I do?

The duplex system is available in the USA, Australia, Canada, New Zealand and the EU. Outside those areas, only InfraRed wireless control is legal.

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