Simply put, unified messaging (UM) is the ability to have all forms of electronic communications gathered in a single inbox. Fax, voice-mail,

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e-mail, and texting are all sent to the same e-mail inbox regardless of their back-end systems. For example, you can have a Microsoft Exchange mailbox, a hosted VoIP solution with voice mail, and a completely separate fax system, yet all of these will place electronic messages into your e-mail box. If you are one of the millions using Blackberry, Windows Mobile or Palm OS services, you will receive these messages on your device as well.
UM is more than a simple notification, however. With UM, you receive the actual voice message as an audio file. This allows you to perform immediate functions on this message: You can listen, delete, forward, and sometimes reply. Faxes, too, arrive as PDF or TIF files.