Furuno Felcom 250 Service Manual page 112

Reference)
1) Changing the password for the Administrator's mode
You can change the password by; Settings -> Change password.
The number of valid characters is 4 to 8 characters.
If you have forgotten the password you had set up, you can follow the procedure
described below;
(1) Login Service mode, Select Settings -> Change password, and register a new
password. The Username cannot be changed from "Admin".
(2) Open; Settings -> Initialize, and select either Initialize except connection
setting or Initialize all to execute the initialization process.
(3) Execute Hardware Reset.
Operations for when having entered Administrator's mode in another PC;
The password for entering the Administrator's mode is the same for other PCs, too.
For example, if you have changed the password from "01234567" to "1234", the
password for entering the Administrator's mode from a PC connected to the
network will be "1234".
If you do not execute any operation for 15 minutes, the screen will return to the
Users' screen.
2) How to change password for entering into Administrator's mode
from the Handset
You can change the password upon each Handset by
selecting; Settings -> Change password. The number of
valid characters is 4 to 8 characters.
If you have forgotten the password you had set up, refer
to page 2-13 to reset the hardware of the Handset.
2.2 Administrator's Mode and Service Mode
2-8