Hi,
You need to turn off the Call Waiting feature for the second call to get the busy signal when you are on a call.
If you don’t wish to do this then the only way to stop the second call going through to messagebank when you have been notified by the tone signal that you have another call waiting, is to answer it by pressing the Flash key on the base unit or the Talk/Flash key on the handset and then telling the caller that you are on a call and to either call back or to wait and then switch back to the 1st call by pressing the same button again. Be aware that there is a slight pause before you connect to either call after pressing the key.
You could always extend the ringtime before being answered by messagebank by dialling * 99 (Enter the number of seconds you wish the phone to ring before a call is diverted (between 5 and 60 seconds) # and hang up. e.g. for 60 seconds dial *9960#.
The above is for Telstra messagebank. If you use a different phone service provider, check their website on how to extend the ringtime for their voicemail service.
This time setting will affect all calls to the number, that haven’t already been answered by the phone’s answering system ringtime setting (6 rings maximum - approx 18 seconds).
If the phone’s answering system hasn’t been setup then the phone will ring for 60 seconds before being diverted to messagebank. The phone’s answering system doesn’t respond to CW calls as there is no ringing current being received by the phone.
You will then need to answer the second call within 60 seconds of being notified by the tone signal that you have another call waiting to be answered otherwise it will be answered by the messagebank service. The 2nd caller will be receiving the ringtone signal as with CW they do not know that you are already on a call.
11 
366 
1.4mil 