Black Box 16 port User Manual page 256

You have lost or don't know your password (as 'admin' user)
• you must reset the unit to its factory default settings using the 'reset' switch on the
rear panel. There is no procedure to access the unit without a password.
at the remote end the client software locks up
other factors: security (CHAP) is enabled on the line.
• disable CHAP re-challenge parameter (challenge_interval) in the unit. Some PPP
client software does not work when receiving CHAP re-challenges.
Black Box Console Server user guide
256