Chapter 4 ________________________________________________________________ Operation  
VAISALA_______________________________________________________________________ 65 
User Port Connection 
Use a suitable serial cable between the user port’s RxD, GND, and 
TxD screw terminals and the PC serial port. 
NOTE 
Do not use the user port when RS-485 module is connected. 
 
Table 10  Default Serial Communication Settings for the User 
Port 
Parameter Value 
Bit rate  4800 
Parity Even 
Data bits  7 
Stop bits  1 
Flow control  None 
 
1 2 3 4 5
6 7 8 9
+
–
RxD
GND
TxD
POWER
CONTROL
USER PORT POWER
RS-232 10…36 V=
IOIOI
 
Figure 37  Connection Example Between PC Serial Port and 
User Port  
Connections to pins 4, 6, 7, and 8 on PC serial port are required only if 
you are using software requiring hardware handshaking. 
After power-up, the barometer (in STOP mode) outputs the software 
version and the command prompt. 
In RUN mode, a measurement output starts immediately after power-
up.