Laird CL4490 Integration Manual page 9

CL4490 Hardware Integration Guide
Version 1.0
Table 2: CL4490 DB9 Male Connector Pinout (as defined in CL4490)
DB9 Pin Signal Name
1 DCD
2 TXD (RXD with respect to DTE)
3 RXD (TXD with respect to DTE)
4
5 GND
6
7
8
9
Interfacing to Other RS232 Equipment
The CL4490 is a DCE (Data Communications Equipment) device. Typically, devices like PCs are considered
DTE (Data Terminal Equipment) devices. Peripheral devices are classified as DCE. A DCE device can interface
to a DTE device using a straight-through serial cable. When interfacing two DCE (or two DTE) devices
together, a null modem (or crossover) cable is required to swap pins and convert the signals accordingly.
Figure 2: DTE to DCE interface (signals with
respect to DTE)
Note: When using a pair of CL4490s to connect a PC to a peripheral unit, if you previously used a
straight-through serial cable to connect your PC to your peripheral device, you'll need to use a
straight-through serial cable between the PC and the CL4490 and a null modem adapter, or cross-
over cable, between the other CL4490 and the peripheral device.
Americas: +1-800-492-2320 Option 2
Europe: +44-1628-858-940
Hong Kong: +852-2923-0610
www.lairdtech.com/ramp
Description
Data Carrier Detect
Transmit Data
Receive Data
DTR Data Terminal Ready
Ground
DSR Data Set Ready
RTS Request to Send
CTS Clear to Send
RI Ring Indicator
Direction
Out
Data Out to Host
Data In to CL4490
In
-
Out
In
Out
Out
Figure 3: DCE to DCE interface (signals with
respect to DTE)
9 Laird Technologies