technical problem with SIM900A in Vodafone

[priyankgoradia]

SIM900A, there was problem of network de-register with some SIM, specially VODAFONE ,,, not able to figure it out the reason for the same , please help to find the solution

 

[speedEC]

Dear Group members,

I need your help on designing circuit which contains SIM900B, PIC MCU and PIR Sensor. Should I use 1000uF cap on VDD pin of SIM900B in order to supply 2A while transmit burst happens. It is so bulky and any other option to replace this bulky capacitor. I didn't see such capacitors on Nokia Mobile SIM Modules. Please note: SIM900B VDD is directly connected to Li_Ion Battery. Also, if transmit burst happens and voltage drop of 300mV occurs. Will this affect PIC MCU and PIR Sensor? If so, How to protect PIC MCU from resetting (or malfunctioning) due to this Vdo problem?

thanks
pmk

 

[speedEC]

SIM900A, there was problem of network de-register with some SIM, specially VODAFONE ,,, not able to figure it out the reason for the same , please help to find the solution

Can you post your GSM Module power supply circuit?

pmk