問題文
The voice messaging platform is to be brought up against three kinds of phone system: a call control cluster, a circuit switched exchange, and an exchange that speaks the scheme which ties private exchanges to one another. What extra hardware, if any, does the guide call for in each of the three cases?
選択肢
- A router acting as a voice gateway for the cluster, a unit placed in between for the circuit switched exchange, and none at all for the last one.
- Nothing at all for the cluster, a router acting as a voice gateway for the circuit switched exchange, and a unit in between for the third one.
- None at all for the cluster, a unit placed in between for the circuit switched exchange, and a router acting as a voice gateway for the third one.
- A unit placed in between for the cluster, none at all for the circuit switched exchange, and a router acting as a voice gateway for the last one of them.