1. Most central office simulators can simulate normal on-hook , off-hook, dialing, answering, speaking, etc.

2. On-Hook is the normal inactive state of a telephone terminal.

3. Then an on-hook signal followed by a quiet termination is transmitted to the originating end until the connection is released by the originating end.

4. As long as a phone does not go "on-hook, " activation of various line pushbuttons will automatically place the first line on hold without the use of a special "hold" button.

5. By the method, when the telephone has a long time without conversation, and the hook switch circuit is in off-hook state, the switch circuit can be changed into on-hook state automatically.

6. Abandonment refers to the network replacement of a connect signal with an on-hook signal (network) prior to receiving a CI (customer installation) answer signal.