NEC MultiSync GT2000 User Manual page 27

Command Communications Sequence
When a command sent from the personal computer has been correctly received by the projector, an "ACK" is returned for the command.
When the command has not been received correctly, a "Receive Error" is sent back. An invalid command will cause a "Command Error".
Note: When an"ACK" from the projector is not confirmed and the next command is received by the projector, an error in
communication can result.
(1) Command (PC to Projector)
Command specification code
(2) ACK (Projector to PC)
*When there is return data
Command specification code
*When there is no return data
Command specification code
(3) Receive error (Projector to PC)
Command specification code
Note: For a complete PC Control Command Reference, see page E-83.
Command
ACK
Receive error
Unit address Function number
Unit address Function number
Unit address Function number
Unit address 00H 01H
EC (Receive Error Codes)
02H : Command error
04H : Checksum error
08H : Busy
10H : Parameter error
20H : Run error
40H : Receiving error on
E-27
Data length Data .............. CKS
Data length Data ............. CKS
00H CKS
EC (Error code) CKS
Projector