I have a set of serial scales. They communicate at 2400 E 7 2. I have used these scales on many other devices so I know they work. They put out a constant stream of data. The O/S is 64 bit Windows 8.1 and I am using a HL-340 serial to USB cable. The drivers came from here http://www.cesareriva.com/release/wp-content/uploads/2011/02/ch341_hl-340_windows_drivers.zip
The drivers installed without a problem and under the device manager I see USB-SERIAL CH340 (COM10) Selecting the properties it says the device is working. I have set the port settings for the correct speed and parity.
I would like to verify that the scales are connected so I am using PuTTY. I have set the speed and parity and the PuTTY log confirms that COM10 has been opened. But I am not getting any data appearing. I would have expected some data, any suggestions?