The Analog Plug is a small board containing the MCP3424 analog-to-digital converter with I2C bus interface. The ADC can take 4…240 samples per second, depending on resolution (12..18 bits). It has 4 differential input channels (just tie the “-” side to ground for single-ended use) and supports a voltage range from -2.048V to +2.048V, full scale.
An I2C bus running at 3.3V is used as interconnect, with all the power and signal lines brought out to to both sides of the board to allow daisy-chaining with other I2C-conformant boards.
The Analog Plug also makes a fine (3.3V) breakout board for the MCP3424 chip, if you wish to use it without a JeeNode. The only thing that is required is a translation of the header signals, DIO is SDA and AIO is SCL.
The Assembled Analog Plug comes with the SMD-sized MCP3424 chip and decoupling capacitor already soldered onto the board. Headers for this and all other JeeLabs plugs can be found here (straight) and here (right angle).
The PCB only version contains just the printed circuit board for the Analog Plug. No parts, no headers.