Huawei MC509 CDMA LGA manual Input Signal Control Pins

It is recommended that use resistance of 0ohm in the DTE to isolate signals transmitted from above pins in Table 3-5

3.4.2 Input Signal Control Pins

The MC509 module implements power-on and power-off and resets the hardware through the input signal control pins.

The power-on, power-off, and reset control parts of the interface of the MC509 module include power-on/power-off interface signal (POWER_ON_OFF) and the hardware reset interface signal (RESIN_N).

The POWER_ON_OFF pin is used to implement power-on and power-off. If the POWER_ON_OFF pin is pulled down for at least 0.5s, the module is powered on; if the POWER_ON_OFF pin is pulled down for at least 2.5s again, the module is powered off.

The RESET pin is used to reset the hardware. When the software stops responding, the RESET pin can be pulled down for 100ms to reset the hardware.

As the RESET and POWER_ON_OFF signals are relatively sensitive, it is recommended that you install a 10nF capacitor near the RESET and POWER_ON_OFF pins of the interface for filtering. In addition, when you design a circuit on the PCB of the interface board, it is recommended that the circuit length not exceed 20mm and that the circuit be kept at a distance of 2.54mm (100mil) at least from the PCB edge. Furthermore, you need to wrap the area adjacent to the signal wire with a ground wire. Otherwise, the module may be reset due to interference.