DS2100N REFERENCE MANUAL
38
4
4.2.1 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:
CBX100/500
Function
TX Transmit
Data
RX Receive
Data
RTS
Request To Send
CTS
Clear To Send
SGND Signal
Ground
It is always advisable to use shielded cables. The overall maximum cable length must be
less than 15 m (49.2 ft).
SGND RXD
TXD
CTS RTS
USER INTERFACE
SGND TX
RX
RTS CTS
SCANNER
Figure 39 – 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 40 - RS232 Control Signals
If the RTS/CTS handshaking protocol is enabled, the DS2100N activates the RTS output to
indicate a message is to be transmitted. The receiving unit activates the CTS input to enable
the transmission.
