USB to TTL 4-pin Wire

Jargon buster

Plain-language definitions for the technical terms used above.

3.3V TTL

3.3V TTL means the serial logic signals use 3.3 volt levels rather than 5 volts. This matters because connecting it directly to a 5V-only signal can damage the module or cause unreliable communication unless level shifting is used.

GND

GND is the ground or reference connection (0 V) for a circuit. When connecting two devices together, their grounds must be joined so both agree on what counts as a low or high signal.

GPS

The US satellite navigation system used by GNSS receivers to calculate position and time. Support for GPS is important because it is widely available and often used together with other constellations for more reliable positioning.

microcontroller

A microcontroller is a small computer on a single chip that runs a stored program and controls connected inputs and outputs such as buttons, sensors, displays and communication interfaces. In a device built around one, it is the part that executes the code and coordinates the device's behaviour.

RS-232

RS-232 is an older serial communication standard that uses higher, inverted signal voltages (typically around plus or minus 3 to 15 volts) rather than the low logic levels of modern microcontroller pins. When connecting RS-232 equipment to a microcontroller, you usually need an RS-232 transceiver or level converter rather than wiring it directly, or you risk damaging the pins.

RX

RX means receive, usually showing data being received by the board. An RX indicator LED can help with troubleshooting USB or serial communication.

single-board computer

A complete computer built onto one circuit board, usually including the processor, memory, ports, and connectors. This matters because accessories like heatsinks must match the board’s layout and mounting holes to fit properly.

TTL serial

A simple serial data connection that uses microcontroller logic-level voltages (typically 3.3 V or 5 V) rather than the higher, inverted voltages of computer RS-232. When a device lists TTL serial, it can usually wire straight to a microcontroller's UART pins or to a USB-to-TTL serial adapter, but it needs a level converter before connecting to a true RS-232 port.

TX

TX means transmit, usually showing data being sent from the board. A TX indicator LED can help you see when the board is communicating or uploading code.

UART

UART is a simple asynchronous serial interface that sends data over separate transmit and receive wires, usually labelled TX and RX, with both ends set to the same baud rate. It is a common way for microcontrollers and other serial devices to exchange data.

VCC

VCC is the positive power-supply connection on a chip or module. Connecting it to the correct supply voltage is needed for the part to power on and helps avoid damaging the electronics.