Connecting to Old Instruments Having +-12V RS232 Voltage Levels

[cstorey]

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The StarTech support told me none of their product supports +-12V

Seems strange, the specs clearly mention 12V.  Were you just asking for USB-RS232?

If you have to create your own, have a look a this - https://www.sparkfun.com/tutorials/215

[Henrik_Volkers]

Or get one of those lower level rs232 to 5V TTL boards and replace that section in the instrument 🙂

Or a USB to serial 5v TTL ....no need for a USB to RS232 adaptor 😄

[Pax_Electronica]

I just received the PCI-8430/2 card. The DTR pin is at -5.3V. On my old Dell PC (Dimension 1100), however, it is -12V.

Now I have to get rid of the PCI-8430/2 card, any takers?