- How do you determine which pins to jumper on DB9 or DE9 male connection serial port on a computer/desktop/laptop when performing a loopback test?
- How to do I perform a loopback test on a USB to RS232 serial adapter?
- Product Family: Message Displays
- Product: Galaxy
- Component: Serial Communication, USB to Serial adapter (e.g. Prolific, Moxa), Computer with 9 pin male serial/COM port
- Control System:
reference How to perform a loopback test with HyperTerminal DD1994747
for performing the loopback test.
- Use a paper clip (or other conductor) to perform loopback and jumper pins 2 & 3 together
- When looking at the serial DE-9/DB9 male connection, go to the column/row that has 5 pins.
- With a USB to serial adapter, orient the adapter so that the 5 pins are on the top (more pins across the top then the bottom)
Vertical Orientation DE9/DB9
- If the column of 5 pins is to the right of 4-pin column, then pins 2&3 will located near top of the 5-pin column (i.e. pins numbered 1-5 top-down)
- If the column of 5 pins is to the left of the 4-pin column, then pins 2&3 will be located closest to the bottom of the 5-pin column (i.e. pins numbered 1-5 starting at bottom)
Horizontal Orientation of DE9/DB9
- If the 5-pin row is located on top of 4 pin row, pins 2&3 will be located closest to the left on the 5-pin row (pins numbered 1-5 from left to right)
- If the 5-pin row is located under the 4-pin row, pins 2&3 will be located closest to the right on the 5-pin row (pins numbered 1-5 from right to left)