TCP :
Transmission Control Protocol. A set of rules to exchange messages with other Internet points at the information packet level.
TCP/IP :
Transmission Control Protocol / Internet Protocol. The basic communication language or protocol of the Internet.
TFT :
Thin Film Transistor, a type of LCD flat-panel display screen. The TFT technology provides the best resolution of all the flat-panel techniques, but it is also the most expensive. TFT screens are sometimes called active-matrix LCDs.
Time/Date Generator :
Installed between a CCTV camera and a monitor, it generates the information of Date, Time and camera ID.
Time Lapse VCR :
A video recorder that can be set to record continuously over long period of time. This can be anything from two hours to 960 hours.
TV Lines (TVL) :
Or lines per picture height, is the number of horizontal alternating dark and light lines on a camera. The higher the TVL, the higher the resolution, but the smaller the angle of viewing is.
Telemetry :
Control of PTZ cameras is provided using Telemetry Control. This signal is sent down 'twisted pair' cable or along the same coaxial cable the video signal is being sent down. Typical Telemetry signals are RS-485 or RS-422.
Tailgating :
1) More than one individual entering a secure area using one access card.
2) Following an authorized person into a secure area. Also Known As - Piggybacking. See Anti Passback.
Telephone Entry :
An access control system that allows users outside a secure area to use a telephone to contact someone inside the secure area and request access.
Timezone :
A specified period of time in which access is allowed. A variety of timezones may be defined to accommodate the access needs of a variety of people.
Transients :
Electrical surges or spikes conducted through power or data lines. Transients are typically generated as electrical devices are turned on or off.
Transorb :
An electrical suppression device. See: Suppression.
Turnstile :
An entryway that uses a mechanical device to restrict entry to one person at a time.
