5.3 CONNECTING RS232 CABLE OF COM1
The serial interface COM1 in RS232 mode is designed as “three-wire”-connection. The
transmission line (TxD) and the receiving line (RxD) are to be crossed in the cable.
PC/TERMINAL
Datalogger DLx
Sub-D25 (25 pins)
cable
Sub- D9
TxD 2
2 RxD
RxD 3
3 TxD
Ground 7
5
Ground
Both sides Sub-D9 (9 pins)
RxD 2
2 RxD
TxD
3
3
TxD
Ground 5
5
Ground
Table 8: Connections COM1 for RS232
5.4 USB
For the communication via USB it is required to have a VCP (Virtual COM Port) driver on the used
PC. Virtual COM port drivers cause the USB device to appear as an additional COM port available
to the PC. Application software can access the USB device in the same way as it would access a
standard COM port.
The driver is available from FTDI (FT245R):
http://www.ftdichip.com/Drivers
In addition installation guides for several operating systems can be downloaded from there.
The USB cable between PC and datalogger is a common so-called AB-plug-cable.
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