Standalone DVR User’s Manual1263.6.1 Audio InputBNC port is adopted for audio input port.Due to high impedance of audio input, please use active sound pick-up.Audio transmission is similar to video transmission. Try to avoid interference, dry joint,loose contact and it shall be away from high tension current.3.6.2 Audio OutputThe audio output signal parameter is usually over 200mv 1KΩ (BNC). It can directlyconnect to low impedance earphone, active sound box or amplifier-drive audio outputdevice.If the sound box and the pick-up cannot be separated spatially, it is easy to arousesqueaking. In this case you can adopt the following measures: Use better sound pick-up with better directing property. Reduce the volume of the sound box. Using more sound-absorbing materials in decoration can reduce voice echo andimprove acoustics environment. Adjust the layout to reduce happening of the squeaking.3.73.73.73.7 Alarm Input and Output ConnectionAlarm Input and Output ConnectionAlarm Input and Output ConnectionAlarm Input and Output ConnectionPlease read the followings before connecting.1. Alarm inputa. Please make sure alarm input mode is grounding alarm input.b. Grounding signal is needed for alarm input.c. Alarm input needs the low level voltage signal.d. Alarm input mode can be either NC (normal Open) or NO (Normal Close)e. When you are connecting two DVRs or you are connecting one DVR and one otherdevice, please use a relay to separate them,2. Alarm outputThe alarm output port should not be connected to high power load directly (It shall be lessthan 1A) to avoid high current which may result in relay damage. Please use the cocontactor to realize the connection between the alarm output port and the load.3. How to connect PTZ decodera. Ensure the decoder has the same grounding with DVR, otherwise you may not controlthe PTZ. Shielded twisted wire is recommended and the shielded layer is used to connectto the grounding.b. Avoid high voltage. Ensure proper wiring and some thunder protection measures.c. For too long signal wires, 120Ω should be parallel connected between A, B lines on thefar end to reduce reflection and guarantee the signal quality.d. “485 A, B” of DVR cannot parallel connect with “485 port” of other device.e. The voltage between of A,B lines of the decoder should be less than 5v.