this is all right in the manual (page 44) as well as in the online versson for the deck on the Pioneer website, just search "DEH-P840mp" and it's under documents. You'll have to make an account on the Pioneer website but it's free.
Setting the time This is used to set the time on the unit's clock display.
1 Press OPEN to open the front panel.
2 Press FUNCTION to select CLOCK. Press FUNCTION until the time appears in the display.
3 Select the portion of the time display you wish to set with left/right. Pressing left/right will select a portion of the clock display:HOUR-MINUTE As you select portions of the clock display the portion selected will blink.
4 Select the correct time with up/down. Pressing up will increase the selected hour or minute. Pressing down will decrease the selected hour or minute.
You would need a car kit (hands free kit) with an audio mute wire that you'd then connect to the mute wire (yellow/black wire) on your deck harness. Your phone would then go into the kit's cradle and when it rang the deck would mute. There are also Bluetooth kits if you have a Bluetooth enabled phone that don't require the phone to be docked.
