Answered: VEXnet Wireless USB Key Alternative

It has come to my attention that the VEXnet wireless USB keys do in fact have an alternative.
From a bit of research, I found that the key is based off of the RT73 chipset from Ralink. Similar keys would be the TL-WN321G which is now out of stock but used to sell for $11.99 or the WUSB54GC which is currently in stock and sells for as little as $30.00+$4.99 shipping.
In addition, searching the actual model number which is listed on the VEXnet key shows that it is the same model as the Tenda W541U which costs an equivalent of $20.
Looking at the specifications for all of these models also show that they have the same ones as the VEXnet keys further arguing that they are in fact the same unit aside from the plastic casing.

Comparing these prices to the $39.99 + $9.99 that the VEXnet USB Adapter Keys ($9.99 for my previous experiences with vex shipping) it makes me seriously question why an alternative is generally not allowed in vex.

Under this premise I would like to ask two things:

  1. Would I be allowed to order these and use them in an official VEX Competition. Of course I would run multiple tests with it in order to ensure that all the connections are fine to each other as well as to the generic VEXnet keys.
  2. What exactly is it in the VEXnet keys that forces them to cost so much. I remember a previous post in which the VEX President commented on how VEX already offers the equivalent of an education discount on all their products. Seeing as how a Tenda key with the same model number costs half as much, or a Cisco key costs $10 less, it makes me, and I’m assuming anyone that will read this thread, why exactly a program that is aimed toward providing the most affordable educational resources possible has an essential part which appears to have substitutes which cost half as much.

On another note, in this post Karthik explains that alternative batteries are not allowed because of safety issues, but the exact same voltage and mAh batteries are created by other respected RC companies. I have to wonder why VEX does not at least provide a list of alternative companies which we would be allowed to buy batteries from.

Hi dreafrea,
Welcome to the forum.

When VEXnet was originally developed and released, there was nothing available suited to what we were trying to do. Utilizing an existing USB Wifi Key as the radio was the best solution available. There is a significant amount of overhead associated with providing a solution such as this – USB keys are, in general, not well suited for use on mobile robotics. USB keys are, in general, not very robust or high quality.

We identified this key design and manufacturer as one which would work for our needs, but only if the keys were extensively screened to ensure only the best ones are used. There was a significant NRE (non-recurring engineering) cost associated with the development of the communication prototcol, the development of the test procedures, the development of the test equipment, and the purchase/construction of the equipment itself. We put every single key through two rigorous tests before they ship out. Approximately 20% of the keys do not pass our screening, and never go out to customers – we do not receive a refund on these scrap keys.

To answer your specific questions:

  1. No, replacement keys are not identical to VEXnet keys and would not be allowed for use in the VEX Robotics Competition based on the current rules. For a variety of reasons the REC Foundation restricts key components to those directly available from VEX Robotics. Consistency & fairness is the big reason – no one from the REC Foundation or VEX can ensure that the items being used by teams are what the team says they are, or that the items are even what the team thinks they are.

This also comes into play when one considers the VEX Robotics Competition relies heavily on volunteer inspectors, many of whom would not be able to correctly verify a team is using a legal item.

These considerations apply to things like VEXnet keys, but also to batteries as you discuss below.

Another consideration is in regard to openness. There are a large number of VEX Robotics Competition participants who would be very, very upset if the VRC GDC opened up the rules in this way. The VEX Robotics Competition is a “sandbox” style engineering competition. Many schools really like the fact that they don’t NEED to go to any other outside supplier – everything is available on This portion of the community is upset enough by the inclusion of things like lexan to the rules. This doesn’t apply so much to VEXnet key replacements, but is also a consideration – especially if “the community” decides that they think some other key is better, and it “forces” teams to go buy that key (regardless of actual performance).

  1. The price of the VEXnet key is driven by the cost of the components, the cost of the overhead associated with its development (as briefly mentioned above), by the additional scrap cost we incur to ensure only high quality keys reach our users, and by the cost associated with a 100% test.

If you or anyone else reading this would like to discuss further, they can email me directly at