CatweazleNZ: I have one of these running on a Freetronics Ethermega. I am only using it to send and receive sms text messages.
The reset pin on these run at 2.8 volts output - you do not supply 2.8 volts to the reset pin. You ground the reset pin momentarily to do a hard reset on these devices.
I confirm you need a separate about 4 volt, 2 amp power supply. A 5 volt power supply may destroy these units. Without 2 amps these units cannot connect to a gsm network.
using LM7805 connected to diode 1N4007, i managed to power up this module. but as you can say, i can't access anything related to SIM, such as AT+CNUM command, it will restart the module, i think it related to power shortage.