Serbian studio Alter Ego Architects has designed a concept for a 3D-printed mobile phone with an interface that only features numbers and symbols, and has no apps to prevent users acting like "mindless zombies" while on their devices (+ slideshow).

With an e-ink screen – similar to a Kindle reading device – the credit card-sized O phone would have no lettering in its navigation so it could be used regardless of language.

Instead, owners would use a series of symbols and numbers to select functions and make calls. It would also feature no apps, and only offer call and text functions.

Novi Sad-based Alter Ego Architects wanted to address the idea that people could be spending more time with their phones than with their families, and propose an alternative to the now ubiquitous smart phone.

"We're spending on average more than three hours per day – almost one day per week! – looking at our cell phones," said the studio. "In order to 'be more productive', we're trying to fit too much stuff in our day, and smartphones 'help' us with this."

"We are actually losing our focus and make our lives complicated," added the architects.

The simple range of features would mean the phone wouldn't need to be programmed to reflect language options for different regions.

"It will be the first phone ever built without language barriers," said Alter Ego Architects, which described the device as "badass".

Following this principle, the phone's name and logo are also a symbol. This can be interpreted as a circle, a ring, or the letter O – pronounced in different languages or dialects.

The phone would be 3D printed and cheap to produce. Its e-ink display would use a very small amount of battery to create a paper-like effect and illuminate with an optional backlight.

Target users would be those who may need to be contactable in an emergency, such as children or the elderly.

It could equally be useful for businessman travelling abroad and people in parts of the world with poor internet connectivity, according to the studio.

In a similar move, Jasper Morrison launched a basic phone with just calling and texting functions for Punkt as a "liberating" alternative to smartphones during London Design Festival 2015.

"Technology is a very powerful tool, but as our lives become increasingly complicated, it is important to find time to disconnect and rediscover the simple things," said Punkt founder and CEO Petter Neby.