Asterisk cards have a different number of ports, due to the variety of needs for different applications, manufacturers try to address them. For beginners, one can request for Asterisk card with single port configured with 1 FXO module. At first, you receive the option of accept incoming calls, afterwards you can route them anywhere within your IP network. It’s only in case of a live call, and than your line is busy because you have a single FXO to handle that call.
IDC projected over 9 billion minutes of voice traffic to travel over worldwide packet networks in 2000, exceeding 135 billion minutes in 2004. Service revenue is projected at 1.6 billion in 2000 and 18.7 billion in 2004.