Serial Converter, Raspberry Pi to Zigbee, RS485, RS232, USB, TTL – Widgetlords Electronics
DIGI ConnectPort X4 - XBee (ZigBee S2B) to Ethernet. Serial (RS-232), Security (5 VPN tunnels and encryption). Includes: US power supply, antennas. - Sapply
Xbee USB adapter
SparkFun XBee Explorer Regulated - WRL-11373 - SparkFun Electronics