AT&T is making a push for business push-to-talk trials for their enhanced PTT, which should be available commercially later this year. They’ve been testing the service since February and feed back has been good so far. The Enhanced PTT service is aimed at enterprise customers and will be available on five smartphones. The technology is designed to deliver voice over 4G LTE, 3G and WiFi connectivity, making it the first voice service over the new LTE network. Enhanced PTT uses technology from Kodiak Networks and supports one-to-one conversations to one-to-many, with up to 250 contacts.