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6. RS-232 & RS-485 Protocol

6.1 Setup

6.1.1 Use a Null Modem cable (the standard RS-232 9 Pin Cable with Pin 2 and Pin 3 exchanged, see pin
configuration chart below for details) to connect the COM 1 on the rear panel of the DVR to a PC.
6.1.2 Set the RS-232 option to ON in the COMMUNICATION page of the setup menu.
6.1.3 Set the PC communication parameters: 9600 bps, No Parity, 8 Data Bits, 1 Stop Bit.

6.2 Communication Protocol:

6.2.0 General Command Format
<Lead Code = 0x41>, < Dest ID >, < Src ID >, <Main category >, <Second category >, {<Number of
parameters>,<Parameter 1>, <Parameter 2> ..,} <End Code= 0x4f>
Lead Code = 0x41
Dest ID = 0x01
Src ID = 0x20
Main Category = 0x01 Keys and Signals
= 0x02 Command
Second Category = 0x01 Handshake
= 0x02 Request Time/Set Time
= 0x06 Request System State
End Code= 0x4f