This test is to confirm whether you have two-way communication on your port.
How to test
Open FactoryWiz DNC
Select a machine
Click Terminal Mode
Unplug RS232 cable from the machine. At the end you just unplugged, have someone hold a paperclip to pins 2 & 3 as shown in diagram, being careful not to touch the paperclip to the sides of connector.
Type a character in Terminal window. You should see the character on the screen and also the same character in a different color next to it if two way communication is established.
You can also perform this test at the port on a serial hub (Quatech, Comtrol or Moxa) or directly on the serial port of a computer (older computer models) or at the end of a USB to serial adapter for more modern computers that don’t have a native serial port.
If the connector is female you have to jumper pins 2 & 3 together by unfolding the paperclip and sticking each end in pin 2 and pin 3 and then performing the test above.