NEC NP-PX700W Command Manual page 7

This is an identification data assigned to each command.
Command :
This sets an identification data assigned to each command to send it.
( See each command description.)
Response :
This returns the 6th bit of received ID1 as HIGH.
For ACK it sends the 8th bit back as LOW (recognized); for NAK it
sends the 8th bit back as HIGH (not recognized).
* ID2: (8 Bit)
This is an identification data assigned to each command.
Command :
This sets an identification data assigned to each command to send it.
( See each command description.)
Response :
This returns the value of received ID2 as is.
* Projector ID : (8 Bit)
This is a projector ID for the projector that sends and receives
frames.
Command :
This specifies a projector ID for the projector that sends and
receives commands. (individual notification)
Entering 00H or FFH 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 projector ID for a projector received regardless of
individual notification or broadcast notification.
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.