Calls without mobile phone or internet: This is now possible with some smartphones – we tried out how well it really works.
Xiaomi advertised its new smartphone Redmi Note 15 Pro 5G (for testing) recently on X (Twitter) with the “offline communication” function: This should make calls possible even without a mobile phone network or internet. This sounds like a cool function, especially in Germany, which has not yet been able to completely shed its reputation as a dead-zone nation.
To do this, two devices establish a direct peer-to-peer connection. The whole thing runs via Bluetooth in combination with a proprietary protocol. Instead of the usual few meters according to Xiaomi At least a range of around two kilometers is possible.
How to enable Xiaomi offline communication
The feature currently only works on a few of the manufacturer’s current models. It was first introduced in September 2025 with the Xiaomi 15T series, and the Redmi Note 15 Pro (+) is now also supported. The devices must each contain an active SIM and be connected to a Xiaomi account. Bluetooth must also be activated.
Step 3
Choose “Everyone” or “Contacts Only” and agree to the terms of service the first time.
Image source: Screenshot/CHIP
Xiaomi offline communication disappoints in the practical test
To test the function, we went to the nearest dead zone: the underground car park under the CHIP editorial team. A colleague stayed at the desk on the first floor with another test device in flight mode – that was the plan. One floor below, his cell phone number was no longer displayed in the overview. Not a good sign.
So instead we tested the function on the same floor. Unfortunately, we discovered that after just a few meters and a single glass door in the way, the connection became so bad that the other person could no longer be understood and the call finally ended. Classic walkie-talkies deliver significantly better results.
The 1.9 kilometer range specified by Xiaomi sounds rather unrealistic after this test. Maybe outdoors, in a very wide field with no obstacles. But on the Product website Xiaomi actually sees offline communication in places like “in underground car parks or at crowded venues“. From our experience, we can’t really imagine this. So the feature currently remains more of a gimmick, especially since it is only available to a few Xiaomi phones.
But the basic idea is quite interesting. If other cell phone brands are also supported and the range could be increased, the function could become an important emergency feature in the future – for example if there are internet and mobile phone outages. Areas with weak infrastructure could also benefit from this.
The messenger app also follows a similar principle, just with chat messages.Bitchat” by Twitter founder Jack Dorsey. You can read more about this in the following article:
About the Author
