Approximately the size of a credit card, these are specially coded cards given to employees and allow them access to secure locations or devices at work. Access cards utilize several technologies such as magnetic strips, Barium Ferrite, proximity (active or passive), and other methods. They are often ‘swiped’ and read by a device that allows the user or employee access.
Similar to a password, this series of numbers or letters enables a user to access a system or computer. At job sites an access code can be the system or process that oversees employees or cars both in and out of certain areas.
These are specific entry points in certain secures areas. A card reader and monitor switches allow authorized entry by individuals with access cards.
ActiveX is Microsoft software component technology, mainly used by Microsoft Windows. They facilitate sharing of information between differing applications. Digital video recorders utilize ActiveX to remotely view security cameras online.
Mutliplexers use this feature, which is a video motion detection technique, to give relay closure for alarms and to improve the update times of video cameras.
AGC (Automatic Gain Control)
Automatic Gain Control. A circuit for automatically controlling amplifier gain in order to maintain a constant output voltage with a varying input voltage within a predetermined range of input-to-output variation. AGC increases the signal strength of security cameras when the light level decreases, and puts a cap on it during higher levels; this keeps the output signal consistent.
AI (Auto Iris)
A useful feature to have in a video camera, an auto iris compensates for variations in light levels, from sunlight to shadows. Essentially, the auto iris opens and closes the lens iris as the light changes; this also prevents the camera from being damaged by very bright sunlight.
When attached to a security camera, an alarm input provides enhanced security in the form of a sensor device, often a door contact or a Passive Infra-red detector for motion detection. Alarm inputs can be self powered or can require external power (usually 12V).
ALC (Automatic Level Control)
Some security cameras feature ALC, which means the camera can bring out detail in bright or dark areas of an image. If too much sunlight makes an image too dark, ALC can focus on the needed image.