[Hilo] how to use AT+KSYNC to indicate the network status?

[Hilo] With Hilo3G module, how do I use AT+KSYNC command to indicate the network status?

Answer: For network status indication, please use <AT+KSYNC=2>.(Manage the generation of signal according to network status automatically)
Note that the output is at PWM (pin 23):

PERMANENTLY OFF Not register/Initialization/Register denied/no SIM card
600 ms ON / 600ms OFF Not registered but searching
75 ms ON / 3s OFF Right connected to the network

Please refer to the AT document for the details of KSYNC.