T15 Controller vs Harmonix OTC
Price, ratings, monetisation and update history for both apps, side by side โ with what reviewers say about each.
T15 Controller
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Using the 'T15 Controller' app on their iPhone, user can now turn 'on' (activate) or turn 'off' (deactivate) their miniature T15 radio frequency transmitter. Previously, either external magnets (for reed switch on/off control) or a separate light control box were necessary. ย The pulses of light transmitted by the iPhone's camera flash contain an embedded code that only T15 transmitters understand. Because the LED flash is so bright and the code is very complex there is no worry that the T15 transmitters will be accidentally receive a command via any other indoor or outdoor light source. In order to reduce the size of the T15 wildlife tracking transmitter (to the smallest size telemetry transmitter in the world) conventional activation and deactivation devices (such as magnetically controlled reed switches) had to be abandoned. This also gives biologists the added convenience of being able to control their T15 transmitters with a device that is normally with them all of the time...their iPhone!
Harmonix OTC
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This app helps users manage and use their hearing aid devices more easily.
Screenshots
Verdict
The clearest difference is update cadence: Harmonix OTC at every 2 days against T15 Controller's every 9 months. On price, ads, in-app purchases and device support there is nothing between them.
Scored on Price ยท Rating ยท Positive reviews ยท Number of ratings ยท Update frequency ยท Ads ยท In-app purchases ยท Monetization ยท Best chart rank ยท Devices ยท Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
T15 Controller ships an update every 9 months, Harmonix OTC every 2 days. The most recent releases landed on September 28, 2026 and September 19, 2026 respectively.
| Parameter | T15 Controller | Harmonix OTC |
|---|---|---|
| Price | Free | Free |
| Update frequency | Every 9 months | Every 2 days โ better |
| Ads | No | No |
| In-app purchases | No | No |
| Devices | iPhone, iPod | iPhone, iPod |
| Requires iOS | 11.3 | 11.0 โ better |
| Further details โ not scored | ||
| Size | 10 MB | 128 MB |
| Age rating | 4+ | 17+ |
| Developer | Advanced Telemetry Systems, Inc. | Huizhou Jinghao Medical Technology Co.,Ltd. |
In-app purchases
T15 Controller
No in-app purchases
Harmonix OTC
No in-app purchases
Questions
Is T15 Controller free?
Is Harmonix OTC free?
Do T15 Controller or Harmonix OTC have ads?
Which is updated more often, T15 Controller or Harmonix OTC?
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