getRSSI()command only indicates the signal strength of the last hop. It does not provide an accurate quality measurement for a multihop link. The command value is measured in -dBm. For example if it returns 0x60, then the RSSI of the last packet received was -96 dBm.
xbee900HP.valueRSSI→ stores the RSSI of the last received packet
xbee900HP.powerLevel→ Stored the power level set