Can't get 2km Rx/Tx WLS102B5B to work

I recently purchased purchased WLS102B5B . :frowning:

I ordered 1 and tried it and it did not work. Instead of returning it because of the low cost of the product I decided it would be quicker and easier to order a second, but it also did not work.

I am having difficulty in getting the two modules to communicate.

I am using 5.0 vdc to power each module, but I also tried 9.0 volts as shown in the photographs,

On the first pair of modules I tied all address lines to a high and on the second pair of modules I left the address lines on both modules in the open position. Neither configuration worked.

I have connected two of the transmitter data lines to 5 volts and left two open.

When I measure the data lines on the receiver they are always low.

When I measure the VT it is always low.

I have read the data sheets on the decoder/encoder IC and understand their operation.

I have used a scope to monitor the the Din pin and it seem to get what I expect on the Data in signal.

There is a place on the circuit board for a capacitor but there is none on the circuit board, in the photographs you can see the wires from the cap through the circuit board.

Many other people on forums indicate that they have also had problems with the modules.

Can you give me assistance to troubleshoot the problem.

rf receiver v3.pdf (176 KB)

HI hanburym
Have they give you a exchange ? And can the new one work right ?