EverFocus ECOR Series Instruction Manual page 104

2-1. Packet Format:
Commands should be sent in packets using the following command string:
Length Byte
Receiver ID high byte
Receiver ID low byte
Opcode Byte
Data Byte
Checksum Byte
2-2. Length Byte
This Length Byte is a prefix.
EX: 0x85 ==> this packet contains 5 bytes. (not including Length byte)
2-3. Receiver ID
ID number can be found by converting the ID in the DVR's Control Menu to hexadecimal.
97