Acer's new Extend concept is a laptop-like add-on to an Android phone. Nick Hide/CNET

BERLIN -- Acer today unveiled a new concept for extending the usefulness of your phone, called, appropriately enough, Extend.

Extend is a laptop-like accessory Acer says could be sold in a bundle with an Android phone for as little as €400 (roughly $530 US, or £340). The two are connected by an MHL cable, rather than docking directly like the similar Asus PadFone.

Acer says that cable saves money, reduces lag, and makes it easier to take a call -- and it lets you use the phone's sensors, too, as I saw with a demo of perennial Android favourite Riptide GP. I controlled my daring jet-ski racer by tilting the phone, with the damp action playing out on the Extend's large screen.

There aren't many concrete specs for the Extend, with Acer yet to decide if the screen will be touch-capable or not. There was a large 6,000mAh battery under the keyboard in the model I saw, which can charge the phone while you use it. Around the sides are a USB 1.0 port for a mouse and a USB 2.0 port for thumb sticks.

The keyboard felt sturdy and easy to type on, and includes a line of Android-compatible function keys along the top. These let you control Wi-Fi and Bluetooth, and quickly call up text messaging, e-mail, and the browser, among other functions.

Document editing was handled by Quickoffice on the model I saw, but of course the entire Google Play store is open to you. As the screen is simply mirroring the phone, whatever will work on the phone will work on the laptop, so Acer doesn't foresee any compatibility issues.

Acer is looking to the developing world with the Extend, where it says the mobile phone is the cornerstone of every business. This will enable people to work on more-professional documents, and type for much longer, without requiring a whole laptop. It could work well for students, too, of course.

With much work still to do -- the mouse was very temperamental, for a start -- the Extend is not a confirmed product, but Acer says if it goes ahead it could appear in the first half of 2014. Are you intrigued by the Extend? Let me know what you think in the comments and check out our IFA home page for tonnes more from here in Germany.