NEC NP-M311W Command Manual page 7

CAUTION :
To notify individually, specifying a model code from the following
model codes is required.
* Model code: (4 Bit)
This is a model code for the projector that sends and receives frames.
Command :
This specifies a model code for the projector that sends commands.
(individual notification)
Entering 0000B or 1111B becomes a common command for all the
projectors. (broadcast notification)
This is convenient for controlling multiple projectors at the same
time.
* When the controller is connected with the projector on a one-to-one
basis Broadcast notification is recommended.
* When the controller is connected with multiple projectors
To control a certain projector, use "individual notification".
For all others "broadcast notification" is recommended.
Response :
This returns the model code for a projector received regardless of
individual notification or broadcast notification.
Table of Model codes
-------------------------------------------
0000B : (broadcast notification)
0001B : MT Series
0010B : LT Series
0011B : SX Series
0101B : GT Series
1111B : (broadcast notification)
CAUTION :
* When the model code is set to "broadcast notification", the command
becomes broadcast notification command, regardless of values of the
projector ID.
* Model code is specified using upper ranking 4 bits of data length.
The lower ranking 4 bits becomes the upper bits of data length.
* Data length : (12 Bit)
This is data length of data portion (unit:: byte).
Command :
This sets data length of data added to a command to send it.
( See each command description.)
Response :
This sets data length of data added to a response to send it.
( See each command description.)
CAUTION :
Data length is specified using total of 12 bits ( 0 - 4095) of 4 bits
of the 4th byte and 8 bits of the 5th byte.* The upper ranking 4 bits
of the 4th byte is model code.