Serial Cable - Trying to make it work

[Oddball]

I have been trying to get my serial interface cable to work without success... ??? .

I have built the cable as shown at this site with the slight modifications as shown at www.customelectronics.co.uk. So far I have not been able to get it to work.

When the 9 pin serial connector is plugged into the computer I have checked the voltages across pin 5 to to pin 8 and also pin 5 to pin 6. Both these voltages are at -8.5V. Should this be the case..??

I have windows98 se and the transmitter is FP-T6NFK.

Friends at work who work in electronics have checked out the circuit itself and it looks fine.

Does anyone have any suggestions to try and fix it to work correctly.??

Thanks for any help.

[Mike Roberts]

Hi

Double check that you have completed the FMS setup - i.e. port address, IRQ + Control settings in FMS. See the instructions on my website.

Then check that you see a small change in voltage accross R5 when you connect your transmitter.

All should be fine with W98 (it is what I have).

Best of luck

Mike

[Oddball]

First of all Mike thanks for the relpy. Much appreciated.

I went to your website and looked at the setup and as far as I could see all was on order. My IRQ for the comport was 4 and the address was 03F8. These were put in. I also check with a voltmeter between pins 4 and 9 of the serial connector on the computer and did not see any voltage change when I plugged in the radio set (with it swtiched on or off).

I was hoping you might have some other ideas/voltages to check.

thanks for any help

Oddball

[Mike Roberts]

I think you need to look closer at your radio, and/or your interface. The fact that you see no change in voltage on R5 when you connect your transmitter suggests there is no signal comming through. Check your lead for connectivity + no short. Do you have access to another radio to check this.

A check you can do with your interface is to connect the input to the +ve rail (diode) and check that the voltage on R5 is more than 12v. Then connect the input to ground (pin 5) and check the voltage on R5 drops to zero. This will confirm your interface is OK.

Cheers

Mike