Rs232 Cts / Rts monitor change on external device

Thread Starter


Joined Nov 4, 2007
I have a LED on a device that outputs around 2v DC.
What I would like to do is tie into this LED on the device to detect when the LED is turned on.
I have cut the positive terminal and tied into it and connected it to CTS on the serial port and am able to detect the signal.
The problem comes in when a USB to RS232 is used on multiple devices.
The CTS / RTS is triggered on all devices.
My thoughts were to put a relay between the LED and have the CTS
hooked to the relay . The problem is I can't find a Relay that trips on 2 volts.
It works fine currently from Regular PC Rs232 issue only is when they are multiple connections via USB RS232 conversion.
Any ideas on how I can possibly use something else to set CTS to high when it detects voltage on a device.
Thanks in advance.