I have been unable to find any documentation relation to I2C connectivity.
The brief reference to it in the Hardware Design guide (V1.4) suggests that I2C is only used in the “Telematics” version when relating to the digital audio (PCM) function.
Dear Wofm,
Thanks for your inquiry in Quectel forum.
Please check the following document, it already modified. Thanks! Quectel_EC21_Hardware_Design_V1.7.pdf (1.5 MB)