eLine Technology iVMS-2000 V2.0.2 - Manual (Page 111)

iVMS-2000 User Manual
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Baud Rate
Baud rate is the number of bits transmitted per second, i.e. 300 bit/s stands for 300 bits
are sent per second; and if the PTZ protocol needs 4800 as baud rate, then it represents the
clock cycle is 4800Hz, and the serial port communication sampling rate is also 48000HZ.
Usually the baud rate for telephone wire is 14400, 28800 and 36600, the baud rate can be set
as much higher than these values, but the baud rate is inversely proportional to the
maximum transmission distance. High bit rate is usually used for short distance
communication, i.e. GPIB device communication.
Data Bit
Data bit is a measure of the actual data bits in communication. When the computer sends
a packet, the actual data bits is not 8 digits, and the standard value is 5, 7 or 8, depending on
how you want to configure the transmission of information. For instance, the standard ASCII
code is 0 to 127 (7 digits), and the extended ASCII code is 0 to 255 (8 digits). If the data
using a simple text (standard ASCII code), then each data packet uses 7 digits information.
Each package stands for 1 byte, including start / stop bit, data bit and parity bit. As the actual
data digits depend on the communication protocol, the term "package" is for any
communications.
Stop Bit
Stop bit is used to mark the last digits of the package, whose typical value is 1, 1.5 or 2.
AS data transmission is schedule on transmission lines, and each device has its own clock, it
is likely that communication between the two devices will not in complete synchronization.
Thus the stop bit does not only stand for end of the transmission, but also provides system
clock synchronization checking. The larger the stop digits, the more endurance of different
clock synchronization, yet slower the data transmission.
Parity Bit
There is a simple error detection way for serial communication which includes 4 detection
mode: even, odd, high and low. (Of course, no parity bit is also allowed.) On even and odd
checking, the serial port will set up a parity bit right, with a value of the data to keep
transmission digits in even or odd number. For example, if data is 011, then the parity bit is
0 to guarantee logic high median is even number. When in odd check, then the parity bit is 1
so that there are three logical high digits. The high and low bit do not actually check the data
information, but only through a simple logic check. This makes receiving devices to know if
there is a noise interferes in communication or whether transmission and reception of data is
not synchronized by digit status.
Hot Spot
Spot on the E-map which is linked with other E-map
Sensor (for E-map)
Spot on the E-map which is linked with alarm sensor input
Saturation
The intensity of a specific hue of color video
Brightness
Brightness is an attribute of visual perception in which a source appears to be radiating
or reflecting light.
Hue
The degree to which a stimulus can be described as similar to or different from stimuli
that are described as red, green, blue, and yellow.
Contrast
The dissimilarity or difference between color brightness
Alarm Box
Device to pick up sensor input and relay output signals
Local Display
Video output directly from the encoding device
Trigger Replay
Output alarm signals under certain interval
Serial Port
Serial port interface
Port
Port address for the protocol, an integer to represent a process
MAC
Media Access Control
Motion Detect