Furuno NX-700A/B Operator's Manual page 30

2. OPERATION
Protecting message from deleting
Messages are automatically deleted from the memory under the following
conditions.
-66 hours passed from the moment when received.
-Older than No. 200
To prevent a message from being deleted, do the follows;
1. Choose the message at the list display.
2. Press the LIST key to show the list options.
3. Choose Lock Message from the list window.
The protect icon ( ) appears next to the message selected.
Note 1: To unlock a message, choose it and then select Unlock Message in the
list window. (The protect icon disappears.)
Note 2: When you unlock a message which was received 66 hours ago or a
message that is older than No. 200, it will be deleted promptly when
unlocked.
Note 3: Maximum each 50 messages for International and local (or 25% of each
memory) can be protected.
2-10
All Messages
Alarm Messages
User Selected Messages
Good Messages
Lock Message
List options