Issue
Verifying the Com Port on a PC is working properly by using "Loopback" test in Terminal Emulator.
Product Line
Andover Continuum, Field Devices, Other, Satchwell MicroNet, Satchwell Sigma, TAC IA Series, TAC INET, TAC Vista
Environment
- Hyperterminal
- RS-232 serial port
Cause
The following test writes to the serial port and reads from the same port. This will verify the Full duplex operation of the RS-232 communication.
Resolution
Short the TX and RX pins of the cable (pins 2 and 3) following the pinouts below. Gender is determined by pin type.
Male DB9 (Left) and Female DB9 (right)
- Launch Hyperterminal by selecting Start>>Programs>>Accessories>>Hyperterminal. If you do not have Hyperterminal, please read Hyperterminal on Microsoft Windows Operating Systems.
- If you are asked if you would like to install a modem, select No.
- Choose any icon and name the session, select "OK".
- In the next Pop-Up menu, choose direct to COMx (where x is the number of the COM Port you are testing.)
- Set the flow control setting to None. Leave the other settings to default settings, select "OK"
- Select File » Properties from the menu bar, select the Settings tab, and then push the ASCII Setup button.
- Check the option for Echo typed characters locally.
- Type something.
If you see double characters the serial port is setup correctly and is functional. The display is showing characters that are sent out and what is read in. The Emulator will send and display the TX and immediately read and display RX.
If you see exactly what you are typing, you have a communication issue. which could be:
- Bad Com Port
- Bad cables
- Pins not shorted correctly
If you are out of physical ports to try, use a USB Serial Port converter.
If you are using a USB, use Reassigning a USB Serial Adaptor to a desired COM port for instructions of assigning Com to another port.
