Panasonic KX-TVM50 Programming Manual page 168

2.8 System Security
Prefix (1 or 2 digits) + Mailbox No.
Specifies the default password for new mailboxes as a combination of fixed digits (1 or 2 digits) and
the mailbox number.
Value Range
1 digit: 0–9 + Mailbox No.
2 digits: 00–99 + Mailbox No.
168 Programming Manual