Aastra MX-OneAastra MX-ONE is a SIP-based communications system offering excellent voice communications combined with a variety of applications to provide a complete range of Unified Communications and Mobility solutions. Aastra MX-ONE is the ultimate IP communications system. It gives you the flexibility to respond to specific communications needs, and to offer users the right services, wherever they are, using the device of their choice. Since voice, data, video and applications all converge over one network - public or private, fixed or mobile - you can access all your office functions such as presence, management applications and phone services, as well as manage your calendar and contacts.