The GPRS shield needs 2A peak current. IDLE mode needs about 22mA; TALK mode is about 250mA; DATA mode highest current is about 450mA. As long as your power supply satisfies the above current requirement, it will work.
The GPRS shield needs 2A peak current. IDLE mode needs about 22mA; TALK mode is about 250mA; DATA mode highest current is about 450mA. As long as your power supply satisfies the above current requirement, it will work.