C7 C7 Audio Visual & Communication Systems 2

Question 1

Which protocol is the industry standard for controlling lighting and AV equipment in modern California commercial installations?

Accepted Answer

DMX-512

Answer

DMX-512 is the standard digital protocol used by C7 contractors for controlling dimmers, LED fixtures, and theatrical lighting in commercial AV installations.

Question 2

What is the purpose of a balun in an audio/video distribution system?

Accepted Answer

To convert between balanced and unbalanced signal formats or impedances

Answer

A balun (balanced-unbalanced transformer) converts between balanced and unbalanced signal types, allowing coaxial-to-twisted-pair runs over structured cabling.

Question 3

Per California electrical code, low-voltage wiring for AV systems run in a plenum space must use cable rated as:

Accepted Answer

CMP (plenum rated)

Answer

CMP-rated (Communications Plenum) cable is required in plenum air-handling spaces because it has low smoke and flame-spread characteristics per NEC Article 800.

Question 4

What is the recommended separation distance between low-voltage AV cables and 120V power conductors when run in parallel without conduit?

Accepted Answer

At least 6 inches

Answer

NEC guidelines and industry best practice recommend at least 6 inches of separation between power and low-voltage signal cables to minimize inductive interference.

Question 5

Which fiber optic connector type is most commonly used for HDMI-over-fiber AV extender systems in California commercial installations?

Accepted Answer

LC

Answer

LC connectors are the dominant choice for modern AV-over-fiber systems due to their small form factor and compatibility with SFP transceivers.

(C7) California C7 Low Voltage Systems Contractor Certification Practice Test

(C7) California C7 Low Voltage Systems Contractor Certification Practice Test

C7 C7 Audio Visual & Communication Systems 2