As years passed, the means to lessen and stop crime has advanced as crime became more complex. For example, from swords and arrows which can actually kill people, law enforcement now has guns and tasers. From bolas and staves which can stop criminals without killing them, law enforcement has developed rubber bullets and tear gas. From chariots and horse-drawn wagons to chase outlaws on horseback, law enforcement now has fast and tough police cars.

Another important development of law enforcement is surveillance. Surveillance has aided the police by monitoring crime-prone areas, checking out suspicious activities that may be a crime in progress. With surveillance, police are able to respond more quickly to a crime scene. Finally, surveillance allows police to gather evidence to convict a criminal to justice.

The foremost equipment in gathering surveillance are surveillance cameras. Sometimes called a CCTV, this modern equipment can zoom in and focus on details, and record images and, sometimes, conversations.

Many people think that surveillance cameras are just units. But, in fact, they are actually part of a larger system. Here, we will look at the important parts that make up this intricate system.

1. Camera – the camera itself is chock full of high technology. Most modern cameras have zoom functions which can focus on a person's face, an identification mark, a strange baggage under his arm, or a weapon under his jacket. And the camera can zoom over a certain target from a hundred or more meters away.

2. Microphone – modern cameras are sometimes equipped with ultra sensitive microphones. Just like a camera lens, the microphone's sensitivity and range can focus on a certain spot. This makes it an ideal surveillance tool for eavesdropping on clandestine conversations and illegal deals.

3. Housing – a camera's housing provides protection for the fragile and sensitive electronics in it. The housing must be tough and sealed; no one wants rainwater or dust coming in to wreck havoc inside camera.

4. Mount – this is a frame or a stand where a surveillance camera is installed. The mount itself is screwed or bolted in places such as top of lampposts, the side of buildings, or inside traffic lights.

5. Servos – servos and gears allow the camera to move, allowing it to follow any target.

6. Computer network – this is the brain of the police surveillance network. The computer network allows operators to control the camera functions and monitor the activities in a given area. The operators manning the computer network also has direct contact with the police department for easy and quick deployment of law enforcement forces.

4. Recorders – Storage systems record and keep images as files to be used when police need to examine these images as evidence for apprehending criminals. In the past, images are recorded in magnetic tapes. Now, with the advent of computers and more advanced systems, the images are now stored digitally.