How to test a serial port RS232? How can I know which RS-232 data lines are active?

Posted by KS Ang on

It is simple, just break the connection, and have a bulb between breaking part.

There are 7 wires:

TD ---- Transmit Data
RD ---- Receive Data
RTS ---- Request To Send
CTS ---- Clear To Send
DSR ---- Data Set Ready
CD ---- Carrier Detect
DTR ---- Data Terminal Ready

Break all the lines and have a wire on again, then it has no difference to before breaking the lines.


What we need is to have a bulb in the middle of the line, then when there is a signal passing on, the bulb will light on.


That’s the way that it work.


We have all the thing inside this tester, so what you need is to have the connection unplugged, then have this tester on, then you will know which data line is NOT active. Of course, we are not using a bulb, we use LEDs instead.


Want to have a look?

SKU: UF000484
available at usbfever

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