NCP Network Protocol Type Format: 'i' - Read-only This value identifies what the network protocol for this NCP. The valid protocol type values are defined by enumeration `SPINEL_PROTOCOL_TYPE_*`: `SPINEL_PROTOCOL_TYPE_BOOTLOADER` = 0 `SPINEL_PROTOCOL_TYPE_ZIGBEE_IP` = 2, `SPINEL_PROTOCOL_TYPE_THREAD` = 3, OpenThread NCP supports only `SPINEL_PROTOCOL_TYPE_THREAD`