Testing direct serial connections

If the connected device is located at the same site (or close enough) as the control center computer, you can establish serial communication. You will use a simple serial cable for the whole distance, connecting the device port to a COM port of the control center computer which runs Trimble 4D Control Server.

You should test the correct operation of the serial communication using the following steps:

1. Connect a computer, for example, a notebook computer, to each end of the serial cable. In order to connect two computers via a serial cable, use a null modem adapter, which twists the Transmit and Receive-lines of the serial cable. Then run a terminal program (for example, HyperTerminal) on each of the computers. Make sure that the keyboard input on both sides is correctly displayed on the other end of the line.

   Tip – Very useful for testing a serial line is a “serial quick-tester”, a serial adapter, which displays the status of the serial lines and also allows switching the wire-connections via DIP switches. You can use this adapter to easily establish a serial line connection between two computers without a null-modem adapter. If you don't know how the serial cable is wired, you can experiment with the quick-tester until you have a correct connection between the two terminal programs.

2. Now connect the device (for example, a receiver at the reference-station end of the serial cable) and either a terminal program or a receiver-brand-specific controller unit at the control center end of the cable. It should now be possible to configure the device via the serial line either using receiver-specific control commands on the terminal program or directly via the controller unit.
3. Now that you have made sure that the serial communication works correctly you can add a receiver-related module for this reference-station to Trimble 4D Control Server and check if it recognizes the receiver correctly and if the receiver starts to send observations to the control center. Also try to reconfigure some receiver settings (for example, the elevation cutoff) and check if the receiver reacts accordingly.