# TC Mobile I/O vs Calibration Keeper

The clearest difference is iOS requirement: TC Mobile I/O at 11.0.0 against Calibration Keeper's 15.1. On price, update cadence, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

TC Mobile I/O ships an update every 28 months, Calibration Keeper every 16 months. The most recent releases landed on October 24, 2026 and October 26, 2026 respectively.

## The numbers

| Metric | TC Mobile I/O | Calibration Keeper |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 28 months | **Every 16 months** |
| Monetization | Free | — |
| Size | 12 MB | 22 MB |
| Requires iOS | **11.0.0** | 15.1 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Phoenix Contact GmbH & Co. KG](https://appshunter.io/developer/426916392) | [Trihydro Corporation](https://appshunter.io/developer/920601995) |

## What reviewers say

### TC Mobile I/O

[App page](https://appshunter.io/ios/app/tc-mobile-io/id1139160079)

Control your TC MOBILE I/O X200 SMS relay with this application. It displays device status and sends commands, eliminating the need for manual SMS writing. Access datasheets and switch between German and English languages.

**Highlights:** Device status indication, Send switching commands, Eliminates manual SMS writing, Data sheet download, Multilingual support (German, English)

**Features:** macOS Compatibility

**In-app purchases:** none


### Calibration Keeper

[App page](https://appshunter.io/ios/app/calibration-keeper/id1465790622)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is TC Mobile I/O free?

TC Mobile I/O is free to download, with no in-app purchases.

### Is Calibration Keeper free?

Calibration Keeper is free to download, with no in-app purchases.

### Do TC Mobile I/O or Calibration Keeper have ads?

Neither TC Mobile I/O nor Calibration Keeper shows ads.

### Which is updated more often, TC Mobile I/O or Calibration Keeper?

TC Mobile I/O ships an update every 28 months, and Calibration Keeper every 16 months. Most recently, TC Mobile I/O was updated on October 24, 2026 and Calibration Keeper on October 26, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*