Справочник Пользователя для Mitsubishi Electronics UD8900U

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The command consists of the address code, ID code, function code, data code, ACK/NAK, and end code. The length 
of the command varies among the functions.

Address code

ID code

Function code

Data code

ACK/NAK

End code

ASCII code

‘30h’ ‘30h’

‘3Bh’ ID ‘3Bh’

Function

Data

‘3Ah’ ‘4Eh’

‘0Dh’

Character

00

;ID;

Function

Data

:N

[Address code] 

Fixed to 00. (‘30h’ ‘30h’ in the ASCII code) 

[ID code] 

 Code specifying the projector to be controlled (For ID, specify either the PROJETOR ID (00 to 
63) or GROUP ID (0A to 0Z). When the code is not specified, all the connected projectors are 
controlled.) 

[Function code] 

Code unique to each control operation.

[Data code] 

 Data (value) unique to each control operation (Not always indicated.)

[ACK/NAK] 

 Code indicating the NAK return as described below

 

 Fixed to :N (‘3Ah’ ‘4Eh’ in the ASCII code. Not added to ACK.)

[End code] 

 Fixed to  . (‘0Dh’ in the ASCII cade)

[Example]  When the personal computer and two projectors are daisy-chained:

Computer

Projector 1

1

3

Projector 2

2

3

4

5

6

5

6

6

Sequence

Note

1

Send the command from the 

personal computer to the projector.

2

The command input from the 

SERIAL IN terminal is sent to the 

projector connected to the SERIAL 

OUT terminal.

3

After receiving the end code, the 

projector sends the return command 

to the device connected to the 

SERIAL IN terminal.

If the projector does not receive commands 

normally, that is, if the projector is not connected 

physically or unable to receive commands, it does 

not send out a return command.

In addition, when the ID code of the command is not 

corresponded to that of the projector, the projector 

doesn’t send a return command.

The projector sends out a return command within 

one second at the latest. 

When the received command cannot be executed, 

NAK is returned (as described below).

4

The return command input from the 

SERIAL OUT terminal is sent to the 

device connected to the SERIAL IN 

terminal.

The personal computer receives the commands as 

many as the number of the projectors that send the 

returned commands. However, 

5

The personal computer checks the 

command and confirms if the sent 

command has been received or not.

6

Use the check command to see 

if the projector has executed the 

command.

This projector sends various codes other than the 

return code. When having a control sequence by 

RS-232C, reject other codes from the personal 

computer.

 •  NAK return

In the following cases, the projector returns the command with “:N” added.
(1) Though the command sent from the computer is received by the projector successfully, it cannot be 

executed because the projector is in the operation prohibition state. 

(2) The data length of the sent command is incorrect or the command is invalid. 
(3) The ID assigned to the command is out of the valid range (other than 00 to 63 or 0A to 0Z).
(4) The signal length of the command is 48 bytes or longer.

 •  When a command is sent out during the following operations, it may not be executed. 

(1) During signal switching
(2) In the process of the auto position
(3) After the power is turned on.
  After the power is turned on, no command is received until the image is displayed. (Usually, it takes about 

20 seconds. However, when the lamp illumination takes time, more time will be required accordingly.) In 
this case, the projector returns the received command with NAK added. 

 •  The return command is sent out within 1 second at the latest. 
 •  When sending commands successively, wait to receive the return command of the current command