14
2. Response code / Error code
 ("h" shows hexadecimal)
The connection ID is attached for the TCP#23's response / error codes are 
used. The connection ID is same as the sending command format.
(1) ACK reply : 06h + yyh                   (yyh : connection ID)
(2) NAK reoly : 15h + yyh
(3) Error reply : 1Ch + 0000h + yyh
(4) Data reply : 1Dh + ××××h + yyh
(5) Authentication error reply : 1Fh + 0400h + yyh
(6)  Projector busy reply: 1Fh + ××××h + yyh 
When the projector is too busy to receives the command ,the projector returens 
the error code. 
In such a case, check the sending code and send the same command again.
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.
Command Control via the Network (continued)