Customers of T-Mobile’s German parent company Deutsche Telekom may soon be able to make VoIP calls over their mobile phones.

The telecoms company has joined a $20m (£10m) investment round - which has been co-led by Intel - into VoIP provider Jajah.

Jajah which has 20 million registered users, uses regular phones and does not require software or special equipment to make VoIP calls.

Instead a user logs onto the Jajah site and types in the recipient’s number. This then connects the call to either landline or mobile phones, for a fraction of the cost of a regular call.

Andreas Kindt, chairman of the investment committee of T-Online venture fund and member of T-Com management board for IT, said the partnership could mean cheaper calls for mobile consumers utilising their mobile web browsers to make Jajah-based calls.

“By investing in companies like Jajah, we will be able to continue to bring users around the world the innovative solutions they are looking for," said Kindt.

Although plans to roll out this scheme to UK based T-Mobile customers have not yet been disclosed, Deutsche Telekom expects to offer to its German customers this in the near future.