pin number
| pin name
| Pin direction
| Pin usage |
| 1 | GND | enter | Module ground |
| 2 | VCC | enter | Module power positive reference, voltage range: 3.3 ~ 5.5V DC |
| 3 | AUX | output | Used to indicate the working status of the module; the user wakes up the external MCU, and outputs a low level during the initialization of the power-on self-test; (can be suspended) |
| 4 | TXD | output | TTL serial port output, connected to external RXD input pin; |
| 5 | RXD | enter | TTL serial port input, connected to external TXD output pin; |
| 6 | M1 | Input (very weak pull-up) | Cooperate with M0 to determine the 4 working modes of the module (not floating, if not used, it can be grounded) |
| 7 | M0 | Input (very weak pull-up) | Cooperate with M1 to determine the 4 working modes of the module (not floating, if not used, it can be grounded) |
| 11 | ANT | output | Antenna interface (high-frequency signal output, 50 ohm characteristic impedance) |
| 12 | GND | - | Fixedly |
| 13 | GND | - | Fixedly |
| 14 | GND | - | Fixedly |
| 18 | NC | - | NC pin, this pin needs to be suspended (for subsequent expansion) |
| 19 | NC | - | NC pin, this pin needs to be suspended (for subsequent expansion) |
| 20 | NC | - | NC pin, this pin needs to be suspended (for subsequent expansion) |
| 21 | NC | - | empty feet |
| 22 | NC | - | empty feet |
| 23 | GND | enter | Module ground |
| 24 | NC | - | empty feet |
