I am just starting to scratch the surface and attempt to understand TTL and serial data ports in general, and am really just trying to put the pieces together and see if I'm on the right path.

First, how do I connect a USB to TTL adapter, such as this one, to my raspberry pi? Do I simply use a USB cable from the pi to this adapter, and then use the pins on the adapter?

Second, will I be able to get readings from a GPS module, such as this one, by wiring it to the TTL adapter?

I ask because I want to attach several devices that require serial data ports to my pi, and as I understand it, the pi only has a single serial data port. So, I'm wondering if my understanding is correct that I can buy these cheap FT232RL USB to TTL adapters and turn my unused USB ports into serial data ports.

1 Answer 1


Yes, This should work with a few caveats (see below). To connect the USB to TTL you would connect a USB cable to the board and then the pins would connect to your GPS module.

This will not provide access to the PPS signal from the GPS module (this may not be an issue depending on your project and its requirements. You can work around this by connecting a GPIO pin to the PPS output via a level shifter.

It is not clear from the linked product page what voltage level is required by the USB to TTL adapter. You will need to make sure that the voltages all match on the power and data lines or use a level shifter.

Since you mention that you are a beginner, it may be worth a few extra dollars to buy from someplace like adafruit who have good documentation and offer support for there products (e.g. there GPS tutorial - which covers exactly what you are asking about - including all the code and software setup needed to make it work)

You will are also likely to receive your order long before an order shipped from China. Buying from China can end up costing you more in the long run - not just in money, but in time, frustration and a project that you lose interest in.

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