Regardless of the telephone operator in use, through the iPhone it is possible to activate the "Mute" function of the "Telephone" app, so that the person with whom you are talking can no longer hear what you are saying. If you are using a GSM cellular network, you also have the option to put a call on hold so that you can make another one. If you wish, you can also set up a conference call with up to five participants.
Steps
Part 1 of 2: Using the Mute Function
Step 1. Make a voice call or answer the one you are receiving
The "Mute" feature can only be used during a phone call. Make a phone call or answer the person calling you, as you normally would.
Step 2. Press the "Mute" button while the conversation is active
The iPhone screen will light up giving you the ability to press the button when you move the device away from your face. Press the "Mute" button to temporarily disable the phone's microphone.
Step 3. Press the iPhone Home button to view the iPhone's home screen
This will give you the ability to check the content of other applications on your device, such as the Calendar app. When you have finished consulting, press the Home button again to return to the current call screen.
Step 4. Press the "Mute" button again to unmute the microphone
This way you can resume the conversation with the other person.
Part 2 of 2: Placing a Call on Hold
Step 1. Make a voice call or answer the one you are receiving
If you're using a GSM cellular network, you have the option to put a call on hold rather than just mute the iPhone's microphone. This feature cannot be used on CDMA telephone networks.
Step 2. While holding a phone conversation press and hold the "Mute" button for a few moments
This will put the ongoing phone call on hold. In addition, both the microphone and the speaker of the device will be disabled.
Step 3. Press the Home button on the iPhone to be able to use other applications
This will take you directly to the Home screen which will allow you to start other programs, such as the Calendar app. To return to the ongoing call screen, press the Home button again.
Step 4. Press the "hold" button to resume the conversation
In this way the call that was on hold will be resumed allowing you to communicate normally.
