Chapter 1
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BB6032-14
Photoacoustic Gas Monitor
LumaSense Technologies
1314i / 1412i / 1512 / 3434i
Page 16 of 81
Fig. 1.9 The RS-232 interface connector of the Monitor
Pin No.
RS–232
CCITT
V.24
Description
Mnemonic
Direction
Shield
AA
101
Protected Ground
P GND
—
3
BA
103
Transmitted Data
TxD
From Monitor
2
BB
104
Received Data
RxD
To Monitor
7
CA
105
Request to send
RTS
From Monitor
8
CB
106
Clear to send
CTS
To Monitor
6
CC
107
Data Set ready
DSR
To Monitor
5
AB
102
Signal Ground
S GND
—
1
CF
109
Data Carrier Detect
DCD
To Monitor
4
CD
108.2
Data terminal Ready
DTR
From Monitor
Table 1.2 Pin definitions of the RS – 232 interface
Data Lines
Pins 2 and 3, Transmitted Data and Received Data, are data lines. For data
lines, RS–232 specifies that:
•
A voltage below –3V signifies a binary 1
•
A voltage above +3V signifies a binary 0
•
When a data line is passive, it is held in the binary 1 condition.
Data transmission is asynchronous as shown in
Fig. 1.10 Asynchronous transmission of character data
