To access, just go to the dialer and dial *#*#4636#*#*. This secret code is not exclusive to the Neptune Pine. It should be available in any Android device. Under Device Info you can find the IMEI, useful battery information, cell signal strength, LAC and CID information.
It is recommended to not change any setting here. In Device info page, you can also set preferred network type. This is set elsewhere to “Automatic”, so don’t change it unless you really know what you’re doing.