Panasonic KX-TGM420 Operating Instructions Manual page 148

Activating/inactivating the remote access code
to play messages
If you activate this feature, you must enter the remote
access code (page 150) to play the new message from
the new message alert call. This is so that
unauthorized parties cannot listen to your messages.
The default setting is "Inactivate".
– "Inactivate": You can listen to the message by
pressing [4] to play new messages (without
entering the remote access code).
– "Activate": You must enter your remote access code
and then press [4] to play new message.
1 [MENU] [#] [3] [3] [8]
2 [ ]: "Remote code"  [SELECT]
3 [ ]: Select the desired setting [SAVE] 
[OFF]
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