12
Command Control via the Network (continued)
7. Reply Data
The connection ID (the data is same as the connection ID data on the sending 
data format) is attached to the Network control commands reply data.
ACK reply: ‘06H’ + ‘xxH’
NAK reply: ‘15H’ + ‘xxH’
Error reply: ‘1CH’ + ‘xxxxH’ + ‘xxH’
Data reply: ‘1DH’ + ‘xxxxH’ + ‘xxH’
Projector busy reply: ‘1FH’ + ‘xxxxH’ + ‘xxH’
Authentication error reply: ‘1FH’ + ‘0400H’ + ‘xxH’
(‘xxH’ : connection ID)
Automatic Connection Break
The  TCP  connection  will  be  automatically  disconnected  after  there  is  no 
communication for 30 seconds after being established.
Authentication
The  projector  does  not  accept  commands  without  authentication  success 
when authentication is  enabled. The projector uses a challenge response type 
authentication with an MD5 (Message Digest 5) algorithm. When the projector is 
using a LAN, a random 8 bytes will be returned if authentication is enabled. Bind 
this received 8 bytes and the authentication password and digest this data with 
the MD5 algorithm and add this in front of the commands to send.
Following is a sample if the authentication password is set to “password” and the 
random 8 bytes are “a572f60c”.
1)
  Select the projector.
2)  Receive the random 8 bytes “a572f60c” from the projector.
3)   Bind  the  random  8  bytes  “a572f60c”  and  the  authentication  password 
“password” and it becomes “a572f60cpassword”.
4)   Digest this bind “a572f60cpassword” with MD5 algorithm.
  It will be “e3d97429adffa11bce1f7275813d4bde”.
5)   Add this “e3d97429adffa11bce1f7275813d4bde” in front of the commands and 
send the data.
  Send “e3d97429adffa11bce1f7275813d4bde”+command.
6)   When the  sending data is correct, the  command will be performed and the 
reply data will be returned. Otherwise, an authentication error will be returned.
NOTE • As for  the transmission of  the  second or  subsequent commands, the 
authentication data can be omitted when the same connection.