Omega Speaker Systems VR200 instruction manual Start-stop Asynchronous Communication, Text

If A < B, then signal = 1

If A > B, then signal = 0

1.4.1 Start-stop (Asynchronous) Communication

The built-in RS-422-A interface communicates based on the start-stop (asynchronous) system. The start-stop system first adds the start bit to the head and then in turn adds the data bits (7 or 8 bits), parity bit, and stop bit(s) to every transmission of each character (see Figure 1.4). Define the address of the RS-422-A interface built in the VR200 recorder, baud rate, data length, parity bit, and stop bit(s) in the SETUP mode on the VR200 recorder.

The start bit is automatically added and thus need not be set.

Idle status of the line

1

0

One character

Data bits

(7 or 8 bits)

Line released due to the idle status (broken line) or continued by the start bit of the next data (solid line).

Stop bit

1

Start bit

Parity bit: odd, even or none

1 or 2

Figure 1.4 Configuration of Each Character in Start-stop System

1.4.2 Text

Each communication data usually contains more than one character, to which a terminator character is appended. This is referred to as a text. See also Figure 1.5.

One character

Terminator

A

B

C

D

E CR LF

One text

Figure 1.5 Structure of Text

The built-in RS-422-A interface identifies each text by regarding the reception of a terminator as the end of the text. See also Figure 1.6.

				Identifies text 1.						Identifies text 2.
A	B		C	CR	LF	D	E	F	G	CR	LF
		Text 1						Text 2

Figure 1.6 Example of Two Texts Where Terminator Is CR/LF

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