The Dutch company KPN’s subsidiary iBasis and the Polish mobile network operator, P4, have announced the opening of international high-definition (HD) voice services, between P4\'s Play brand, in Poland, and KPN in the Netherlands, Telecompaper.com reports, noting that Play and KPN mobile users can now call each other with HD Voice’s high-fidelity service.

HD Voice delivers crystal-clear audio by reducing background noise and using a wider frequency range. Play introduced HD Voice in 2012 and provides domestic HD voice service for Polish customers. KPN introduced HD Voice to its mobile network in the Netherlands in early 2012.

Today, HD Voice is used on more than 100 mobile networks in 71 countries. There are more than 320 HD-Voice handset models on the market, including Apple’s, Samsung’s, and Nokia’s.