FMC will give you the connectivity needed to provide true mobility to your end users. Without it, your mobile number, and your landline number, would be two stand-alone connections in the office phone system. People calling to your mobile phone will not know that you might be busy in another call on your landline number, or the other way around. With FMC, you can have both a mobile number and fixed number, simultaneously connected to the exchange. They will both ring, regardless of which number was called, and both will know what your true line state and presence are.