Hitachi CP-X205 User's Manual And Operating Manual page 109

The TCP connection will be automatically disconnected after there is no
Authentication
The projector does not accept commands without authentication success
when authentication is enabled. The projector uses a challenge response type
commands to send.
1) Select the projector.
send the data.
reply data will be returned. Otherwise, an authentication error will be returned.
NOTE
authentication data can be omitted when the same connection.