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By fgnievinski
#192499
Hi. I purchased this USB-to-TTL cable: https://www.sparkfun.com/products/12977

The spec says the VCC pin operates at 5V, but when I test it with a multimeter, it gives zero.
RX/TX seem fine as testing TX & GND gives constant 3V and RX + GND gives oscillating 3V/2V.

The Arduino IDE Serial Monitor shows data if I use the serial cable's RX/TX wires and power up the device using VCC/GND from a battery. I wanted to use the serial cable's four wires instead of only two.

Any ideas on how to further debug if the cable is faulty or if I'm missing something?

Thanks,
-FGN.
By jremington
#192502
It sounds like the cable is faulty. I would contact Sparkfun for a replacement.