Q-See QSD371614C4-250 - Manual (Page 33)

Operation Manual-4CH Duplex DVR
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11.3 System Connection Diagram
Note: We STRONGLY recommend that you plug the DVR and cameras into a Transient Voltage
Surge Protector (UL-1449 rating). Look for a clamping voltage of 330 or lower, Joule rating of at
least 400, and a response time of 10 nanoseconds or less.
11.4 DVR Accessories (included)