TA-521 Full Duplex, Open Mic Radio – My Review

Filed under Football (Soccer), Uncategorized
A set of Full Duplex Referee Radios for under $500? I just had to try them out!

A set of Full Duplex Referee Radios for under $500? I just had to try them out!

Note: NONE of the links I provide in this article are affiliate links. I receive no money for anything posted in this article.

All prices are in US Dollars, and are current as of March 2015.

Last week, I ordered a set of TA-521 radios from a company in China called TA-RF Security. I have provided their contact information at the bottom of this article. While I already have two sets of Push-to-Talk radios (RefTalk, and a DIY setup that I made using a set of Midland GXT1000VP4 radios), the key selling point of the TA-521s is the fact that they are open-mic (the microphone is always on, so you just speak without pushing any buttons), and full-duplex (you can hear everyone else even while you are talking).

At the moment, there are three popular full-duplex radio brands available to referees: RefTalk2 (pronounced “RefTalk squared,” currently priced at $2,100), the Vokkero series of radios (an entry-level, 3-user kit starts at $2,200), and the Eartec ComStar series (a 3-user kit costs $1,600).

I purchased my 4-user TA-521 kit for…wait for it…$504. Including shipping. It was actually $480; the other $24 went directly to PayPal in the form of transaction fees. (Note: As of September 2015, the price of the set has increased to about $525.)

Obviously, if you’re still reading, you want to know if these radios are actually good enough to compete with setups that are three to fours times as expensive. There is so little in terms of reviews of any full-duplex radios out there, and nothing at all about the ones I purchased. So, here is my review of the TA-521 radios. I will provide as much detail as possible, as objectively as possible. This will be a long post.

Another note: Throughout 2015, this article will be a work in progress while I continue to test the radios in game situations, and come up with solutions to any issues that I encounter. This article was last updated on September 9, with a price update.


First Impressions


First of all, looking at a picture of the TA-521, and a picture of the RefTalk2, you might notice that they are remarkably similar to each other. They even seem to have the same case layout! I’m not going to speculate, but I will mention that the original RefTalk radios (click for a picture) were really just Tekk XU100 radios (click for a picture), rebranded with a RefTalk logo. This was clearly evident, as the “XU100” model name was right there on the front of the RefTalk1 radio, just above the LCD screen. If the TA-521 and the RefTalk2 do use the same electronics, then that’s a huge positive for the TA-521, as you could be sure that it is just as good as the RefTalk2. It is possible, however, that the TA-521 is simply an attempt to copy the RefTalk2, with lower-quality electronics.

TA-521 (left) and RefTalk2 (right) side by side.

TA-521 (left) and RefTalk2 (right) side by side.



The TA-521 is very small. With a length of about 10cm (not including the antenna, which adds another 8cm to the length), it is only slightly taller than the original RefTalk, while much thinner at about 2cm thick. The antenna on the TA-521 is detachable, if you want to switch it with another SHA-type antenna, such as the smaller one found on the Tekk XU100. These radios are also very light; probably about the same weight as the tiny RefTalk1 radios, and much lighter than the bulky Midland radios I used to wear. The specifications say that it weighs 135 grams, or about a quarter of a pound.

Click here for a picture of the TA-521, RefTalk1 (Tekk XU100), and Midland GXT1000VP4 side by side.



The bottom of the TA-521. From left to right: 3.5mm and 2.5mm microphone inputs, 3.5mm headphone output, power switch.

The bottom of the TA-521. From left to right: 3.5mm and 2.5mm microphone inputs, 3.5mm headphone output, power switch.

On the side of the radio is a mini-USB port for charging the device (charger included).

There are three ports on the bottom of the TA-521. You’ll see two microphone inputs (one is 3.5mm, which is the size of the jack on a standard pair of headphones, and the other is 2.5mm, which is standard on most two-way radios), and one 3.5mm audio output.

Now here’s where the radio has its first problem – and it’s a big one.

The strange thing about the output is that it is a stereo output, rather than mono. I say this is strange, because it means that nearly all standard two-way radio headsets will NOT work with the TA-521, since they all use mono jacks! This means that, while this radio can fit a standard S2 headset (like the ones used with Midland radios), you will only be able to speak; you won’t hear anything through the headset unless you convert the stereo signal to mono first. I have spoken with TA-RF, who say that they may change the jack to a mono output in the future. (EDIT: It has been 3 months, and they have still not changed it. They say it’s because they are working on “other projects.” I say they have no intention of ever fixing this issue.)

Here is the good news, though: Converting the stereo signal is actually very easy, and cheap, to do. As an added bonus, since you’re going to add two additional connectors anyway, this means that you can make the TA-521 work with nearly any two-pronged headset, such as the M1 headsets that come with RefTalk1 and some Motorola radios, or the K1 earpieces that work on Kenwood devices.

The easiest way to make the modification is to buy two small adapters: First, get a 3.5mm female mono to 3.5mm male stereo adapter. After some trial and error, this is the one I finally ended up using. It has two female plugs, but you only need one. The black one works fine, so I never tried the red one. Of course, you will need four of these adapters, since there are four radios in the set. I’d recommend buying more than 4, in case one or two fail. This adapter connects to the larger prong on the S2 headsets.

You have two choices for the other adapter. You can connect the 2.5mm prong to either of the two microphone inputs on the TA-521, so either buy a 2.5mm female to 3.5mm male adapter, or get a 2.5mm female to 2.5mm male extension cable (not common, and usually comes as a long cable!). The picture below shows my first setup, where I bought the 2.5mm to 3.5mm adapter (the gold one).

adapter mod

This proved to be difficult to deal with on the field, since it was easy to knock loose, and easy to break the headset prongs because of all the pressure on them (which I did on the first trial). I do NOT recommend using an adapter like the gold one above. I now use a 2.5mm to 2.5mm extension cable, though the shortest one I could find is 3 feet long.

adapter mod 2

If you’re working with a K1 headset, the only difference is that the two prongs are switched; the larger, 3.5mm prong is for the microphone input, and the smaller, 2.5mm prong is for the audio output. You would buy the red and black adapter, plus a 2.5mm female to 3.5mm male cable (not an adapter like the gold one), and connect them to the 1st and 3rd ports on the radio.

If you have an M1 headset…good luck. The prongs are so close together that you will probably not be able to fit both adapters onto the headset at the same time without some creativity (i.e., an Exacto knife and a nail file).


What’s in the Box


Included in the case, in addition to the radios, were 4 of each of the following: wall socket USB chargers with mini-USB cables, soft cases, velcro arm bands (tip: wear them inside out so the radio doesn’t move), and the most awful, uncomfortable earpieces I have ever worn. You’ll definitely want to buy your own earpieces and use adapters, as described above. Personally, I use these secret service-style tube earpieces, but I have also used boom mic headsets with little fuss. RefTalk’s boom mic headsets are actually really good; I would recommend buying theirs if you’re willing to spend $60 for each one. The cool thing about the secret-service-style tube headsets, is that the PTT/VOX switch simply acts as an “On/Off” switch for your microphone. If you don’t want to be heard, flip the switch to “PTT” and you can speak without your mic picking it up.

If you use the tube earpieces, it is a good idea to buy a bunch of spare earbuds, since most people don’t like the idea of putting something in their ear that someone else has already used, even if you cleaned it first. This ebay listing sells 40 earbuds for $17. Forty earbuds should last about 3 months, depending on how many different refs you work with.

While I do use the supplied arm bands, I’ve never been a fan of arm bands in general. I have purchased a set of running belts, but I haven’t tried them out yet. You could also try the belts that come with the RefTalk radios, since they are (in theory) specifically designed for a radio of this shape. You can find them on the RefTalk website (scroll down to “RefTalk Accessories”).


Sound Quality


The TA-521 radios sound good for my purposes. I wouldn’t listen to Mozart through them, but they work just fine for speech. I found the sound to be quite “warm” and “analog,” if that makes any sense. You quickly get used to the “echo” effect of a someone shouting something loudly, followed by you hearing it again because it was picked up by someone’s mic. There is a delay of about half a second, so it might be annoying to try to speak to your crew at close range with your mic still turned on. From a distance, the delay is not noticeable.

You can improve the sound quality, if you wish, by investing in a good earpiece. Though I’ve already mentioned buying generic silicone earpieces in bulk, you could spend a little extra on your own personal earpiece, since you’ll be using it regularly. You might consider a foam earpiece that can mold to the shape of your ear, such as this one. Or, of course, you could always splurge for a custom-fit earpiece as well! (EDIT: After trying out some different earpieces on the field, I found that my favorite one was…the generic silicone earbud from eBay. Go figure! It was the only one that I never had to touch or re-adjust while it was in my ear.)

The main advantage that an open-mic system has over a push-to-talk setup is the quick response time. There are situations where an AR might not have enough time to find a button, and press it, all while trying to focus on their responsibilities on the field. Another benefit that I really like is that you can get used to the other referees’ voices, since the mics are always on. One problem that I had with my push-to-talk systems was that, if I wasn’t expecting to hear someone’s voice, and they suddenly started speaking, I would miss the first couple words that they said. With this open-mic setup, everything flows like a real conversation would, so it’s easy to understand exactly what the crew is trying to tell you.

One question I know many people will have is, how does the whistle sound through the earpiece? Well, it turns out that the whistle’s high pitch doesn’t actually get picked up by these radios! I don’t know if the manufacturer designed them like this, or if it’s just because the radios are cheap, but my ARs reported that they never actually heard the whistle coming through their earpieces; they could only hear it on the field (EDIT: In later trials, I was able to hear the referee’s whistle while working as an AR, but it was quiet and low pitched, probably because the higher frequencies could not be detected by the cheap electronics). The loudness of the whistle was actually one of the things I was most worried about when purchasing the TA-521s, but it turned out to be a complete non-issue.


On the Field


My first trial with these radios was on a low-level Boys U13 game. The other refs knew it was overkill, but they were willing to help me test the radios so I could have something to write about in this article! The bad news: my radio was cutting out for most of the game, because I did not secure the wire connections properly, and they kept getting knocked loose. The good news: I learned a great deal from the experience, and the two refs working as my ARs that day, Doug and Dave (whose radios worked just fine for the entire match), were absolutely hilarious, so while my radio was working, I got to enjoy their back-and-forth banter with each other.

After waiting nearly four months, I finally had a chance to take what I learned and try again. I brought these to a reasonably high level youth tournament in my home state. The other refs did not know about the radios in advance this time, but were happy to try them out for our set of 5 games (three U17 Boys, and two U13 Boys). It was cold, windy, and raining on and off most of the day. The radios performed great.

Without exaggerating, I can say that this was one of the best sets of games I have ever worked in terms of match control and referee teamwork (and this was with 4 months of rust for all three of us). I have never been so “on the same page” with a ref crew as I was at this tournament. All three of us were engaged 100% for every minute of every match. We kept track of foul count together, helped each other remember which players had been already spoken to, which players are getting close to being cautioned, and so much more. Those “push in the back” calls on aerial challenges that are sometimes difficult for the referee to see (but are crystal clear to the AR with wider view and better angle) were dealt with every single time, because the AR could alert the referee without attracting dissent by waving the flag from 50 yards away.

We kept adjusting our pre-game as the day progressed, based on what we learned in the earlier games. By the middle of game two, we pretty much had the strategy down, so here is what we did: Most of the time, when everything is fine, we would say “good” or “all clear.” When one of us wanted to “suggest” a foul (meaning “I think I saw something illegal, but you’re closer so it’s your call”), we would actually say “foul” (or “push,” or “trip”). I know it sounds like a command, but we agreed that it was the best way to quickly make the suggestion. Some of the time, the person with the better angle would simply say “yep, I saw it,” and we would move on (meaning, “thanks for being alert, but it wasn’t as bad as it looked from your angle”). On a couple rare occasions, the whistle would sound, followed by “Thanks! No idea how I missed that!” The other times, the referee would simply blow the whistle because they saw the same thing (or weren’t sure, but the suggestion confirmed it).

When one of us had something 100% (a situation where the AR would normally flag, but in this case, it might be inappropriate because of the distance), we would say “whistle.” The referee would immediately blow the whistle, and we could then explain what happened. We ended up doing this twice all day: once for a player who had collapsed with no one near him (he was okay), and once for a head injury. So basically, “whistle” meant “stop the game right now, before we get sued!” Some other appropriate times for this command might be to stop the teams from restarting before a substitution is completed, or to tell the referee that you just saw a lightning strike.

For offside, the AR would actually say “he’s off” to let the referee know that there might be a flag. “He’s off” actually meant “He’s in an offside position, but I’m waiting for him to be involved in the play.” No whistle would come until the flag actually went up.

Amazingly, this system worked extremely well for us. Thinking about it now, I can’t remember a single day before this one where the ref crew had absolutely nothing to discuss or debate at halftime. We didn’t debate anything over the radio either. It was as close to “one mind” as a ref crew could possibly get. Now, it could simply be because I was working with two fantastic officials, but I’d like to think the radios helped!




Overall, I was very impressed by these budget radios. The only thing I’m disappointed about is that I waited until the last game of my fall season to actually try them out, so I had to wait through the entire winter before I could use them again and give a proper review! If you have $2,000 to spend on the real thing, then go ahead and buy the RefTalk2, Comstar, or Vokkero systems. They require less effort, and they probably have some sort of warranty on them! If you want something that can definitely hold its own compared to those more expensive radio sets, while spending about $600 total (if you buy the additional accessories that I recommend at the end of this article), then you will not be disappointed by the TA-521 radios.


How to Purchase


If you want to buy a set of TA-521s, I would recommend buying them from the same company that I used, TA-RF Security. While there are several other Chinese companies who advertise this same radio, I have only done business with TA-RF, and that was after a lot of research.

TA-RF Security do a lot of their business on Alibaba. In fact, that’s where I found them. I know that a lot people have been scammed through Alibaba, so I asked TA-RF Security if I may share their contact information in this review, which they were happy to allow. Their website is here, and their very helpful Sales Manager, Andy Yam, can be contacted via email: andy@tech-an.com. If you plan to purchase, I would recommend just emailing Andy and telling him you’re a referee looking for the TA-521. Again, I receive nothing for this referral.


Summary of Parts


This is a list of every part I purchased to make these radios work, with a link to where you can find it.

Headsets: Midland AVPH3 Transparent Security Headsets with PTT/VOX switch. This listing is sold as a pair, so buy 2 pairs to get 4 headsets.
Adapter #1: Hosa YMM-261 3.5mm TRS to Dual 3.5mm TSF. You don’t need the red portion of the adapter, but these are small and cheap. Buy 4.
Adapter #2: Monoprice 2.5mm Extension. This is the shortest one I could find for a low price. If you want a shorter cable, expect to pay 6 times the price. Buy 4 of these. Note: Do NOT buy a “3 ring” adapter that looks like this. They don’t work with these radios.
Earpieces: Silicone Earbuds for Midland Headsets. I believe this is a standard size, so it doesn’t matter what brand you buy. Expect to give an earbud to a ref to use one time, then throw it away. Buy enough of these so you don’t run out!
Belt Pouches: Gear Beast Weather Resistant Waist Pouch. A good, inexpensive replacement for the arm bands, if you don’t want to use them.

Clear Tape: 3M Transpore Tape. I use a small amount to hold the tube earpiece in place, not because the earpiece falls out, but because the tube itself will sometimes stick out from your neck at strange angles, looking unsightly and unprofessional. Usually a small piece on the side of the neck (below the ear, and above the coiled part of the tube) is enough to prevent this annoyance. I use an extra piece of tape below the coiled part of the tube as well, but it’s not necessary.
Accessory Case: Flambeau Tuff Tainer. I never remove the radios from the leather cases, so they no longer fit in the original case with the rest of my accessories. I bought this (at Wal-Mart, but the link is roughly the same price) to hold all the small parts.
Gaffer Tape: Pro Tapes Pro Gaff. Used to keep all the excess wire together.
Alcohol Pads: Curad Alcohol Wipes. These are not the ones I bought (I got mine at Wal-Mart). Clean your earpiece after use, and wipe the plastic tube clean after removing the clear tape, or else it will get sticky.
Rubber bands and an exacto knife will also come in handy for the initial setup, as you will see below.


Putting it All Together


Here is one example of how to put everything together into a neat little pack that won’t get knocked loose while youre sprinting around the field.

Put the radios into the leather cases, and never take them out again. Cut a hole in the clear plastic on the side of the case with the USB port so you can charge the radio without removing it from the case.

To secure the adapters: First, connect the adapters to the headset jacks, and secure this connection with a thin piece of gaffer tape over the top.

cable tape vert


Wrap the adapter cables with a rubber band to hold it together. I do this before wrapping the gaffer tape around it so that I can make small adjustments first. You can also wrap the headset itself with a rubber band, just to keep it out of the way.

cable rubber bands

Once you’re satisfied with the way the adapter wires are sitting, wrap a piece of gaffer tape around it all. Do NOT wrap the actual headset with gaffer tape, obviously!

cable tape final

Now I will make the connection between the radio and the adapter cables a permanent one (or at least as permanent as gaffer tape will allow!). You may not want to do this, but it does give your radios a neater look. First off, connect the arm band to the leather case. This will prevent you from placing the gaffer tape too low on the radio, which will make it impossible to connect or disconnect the arm band later. Even if you don’t plan to use the arm bands, you should still follow this step, just in case you or a crew member ever decide to use one!

Next, connect the two adapters to the radio. At this point, you might want to test the radios and make sure you’re connecting them properly! Turn on another radio and make sure you can talk and listen with both of them. Once you know that everything is working, wrap a small piece of gaffer tape around the two adapter jacks while they are still connected to the radio. This guarantees that the jacks will be lined up perfectly with each other.

tape jacks 1tape jacks 2

Next, use your thumb to hold the adapter cable bundle against the front of the radio (the side with the leather loop for the armband). You can also use a rubber band to hold it in place. Don’t position the cables too high up on the radio, or else the adapters have room to disconnect from the radio. You also shouldn’t place them too low, or you will put too much pressure on the metal prongs, which could cause them to bend or break.

tape hold

Once the cables are sitting nicely on the front of the radio, wrap a long piece of gaffer tape around the top half of the cables and radio. Make sure that the tape is not blocking the arm band from moving freely. To get more space for the tape, pull the arm band as far down within the loop as you can. You should now have a radio that looks like this:

tape last

And here is the entire unit:

tape result

If you are going to use a waist pouch instead of an arm band, then you may not want to tape the wires to the radio, since everything will be secure inside the pouch.

For best fit, wear the radio with the antenna pointing down, with radio’s leather case sitting directly against the side of your arm, between your tricep and deltoid muscles (basically, as high up as you can get the arm band). It should be in your armpit! This is a picture of me wearing the unit before completing the final steps above, just to illustrate how the unit can be worn comfortably. I actually wore it just like this on my second trial, and it never budged once in 6 hours of use.

chas radio

I hope that helps! Any questions, post them in the comments below.