Specifications

Document Number 3PCI-0712m Appendix D D-1
Figure 33. RS-232 Loopback w/Handshaking Connections
2. From the Windows Desktop click Start → Programs → B&B Electronics
→ ComTest → ComTest.
ComTest will start and then open the Select Port dialog box.
3. Select the COM port you want to access or test. (The drop down box shows
available ports that are not currently in use).
4. Click OK. The Configure Port dialog will appear.
5. Select the desired baud rate, parity, data bits, stop bits. (Defaults are
common settings).
6. Type characters. They will appear in the upper window.
If you are performing a loopback test, you should see the characters appear
in the lower window as they are received.
7. On the Option menu, click DTR to assert or de-assert the DTR hardware
handshake line. The DTR indicator at the bottom of the window will be red
when asserted.
If DTR is looped back to DSR and DCD their indicators should also be red.
8. On the Option menu, click RTS to assert or de-assert the RTS hardware
handshake line. The RTS indicator at the bottom of the window will be red
when asserted.
If RTS is looped back to CTS, the CTS indicator should be red.
9. When testing is completed, close the program.