To Use Call Waiting:
When you are on the telephone and hear a “beep,” you have three options:
1. Hang up. This ends your first call and the phone will ring. Pick up the receiver and you are connected to the second call. 
2. Depress the switchhook for ½ second. The first call is put on hold and you are then connected to the second call. Alternate between calls each time you depress the switchhook for ½ second.
3. Keep talking to the first call. The second call will not interrupt you. They may think you are unavailable because they hear the phone ring. 

To Cancel Call Waiting:
Cancel Call Waiting tones when you do not want to interrupt a special telephone call or computer transmission.
1. Pick up the handset.
2. Press *70.
3. Wait for the special dial tone.
4. Enter the telephone number. You can now carry on a conversation or computer transmission without interruption. Call waiting is automatically reactivated when you hang up the phone.