LabComm collects data from an analyser by connecting to a port on the analyser. This can be a LAN (RJ45), USB, or Serial (RS232) port.
The majority of analysers use serial ports to send and receive data from. Serial ports are also known as RS232 ports. RS232 ports can have different pins or connections within the port and this may require that a cable with specific pin configurations be made up. We can provide the correct serial cables. The end user who wants to interface to an analyser using LabComm would not need to worry about the cable configurations - we are providing this information for reference and guidance only.
There are several possible Null modem cable configurations. The “standard” pin outs are shown below.
9-Pin ConnectorRXD pin 2 ---------------------------------------- TXD pin 3
TXD pin 3 ---------------------------------------- RXD pin 2
DTR pin 4 ----------------------------------------------- DSR pin 6
GND pin 5 ---------------------------------------- GND pin 5
RTS pin 7 ---------------------------------------- CTS pin 8
CTS pin 8 ------------------------------------------ RTS pin 7
This can also be displayed in a graphical format:
- Simple null modem without handshaking
We can start with this cable. It is the simplest to understand as there are only three lines in use - the signal ground and the transmit and receive data lines. This means that one wire transmits the data, a different wire sends the data and one wire acts as the signal ground
- Null modem with loop back handshaking
This is the nearest to a “standard” and matches the pinout drawing first shown. This is used for the majority of analysers.
- Null modem with partial handshaking
- Null modem with full handshaking
