25-PIN CABLE ELECTRICAL CONNECTIONS
61
5
5.2.1 RS232
Interface
The serial interface is used in this case for point-to-point connections; it handles
communication with the host computer and allows both transmission of code data and the
programming of the scanner. This is the default setting.
The following pins are used for RS232 interface connection:
25-pin
Name
Function
2 TX
Transmit
Data
3 RX
Receive
Data
4
RTS
Request To Send
5
CTS
Clear To Send
7 GND
Ground
It is always advisable to use shielded cables. The overall maximum cable length must be
less than 15 m (49.2 ft).
DS4800
7
4
5
3
GND
RTS
CTS
RX
TX
2
USER INTERFACE
GND
CTS
RTS
TXD
RXD
1
Chassis
Figure 50 – RS232 Main Interface Connections Using Hardware Handshaking
The RTS and CTS signals control data transmission and synchronize the connected devices.
START
OF
TRANSMISSION
END
OF
TRANSMISSION
+ V
RTS
- V
+ V
TX DATA
- V
+ V
CTS
- V
DATA
TRANSMISSION
DATA
TRANSMISSION
C1 C2
C4
C3
C5
TRANSMISSION
STOPPED
ENABLED
DISABLED
ENABLED
IDLE
IDLE
Figure 51 - RS232 Control Signals
If the RTS/CTS handshaking protocol is enabled, the DS4800 activates the RTS output to
indicate a message is to be transmitted. The receiving unit activates the CTS input to enable
the transmission.
