This is my first touch to this relatively new technology.
So what is 802.15.4 or so called Zigbee?
It is a wireless data transfer on low/medium distance at low power.
Frequency ranges:
- 868 Mhz – 1 channel – BPSK mod – raw 20 kbit/s
- 915 Mhz – 10 channels – BPSK mod – raw 40 kbit/s
- 2.4 Ghz – 16 channels – QPSK mod – raw 250 kbit/s
As you can see ZigBee does not try to do the same as WIFI or Bluetooth – it is not its a rival. ZigBee’s specialties are
1. Low power consumption
Multi-month to multi-year battery life time
2. Low to mid range availability
10 – 75 meters
3. Low data transfer
250kbit/s by 2.4 Ghz of raw data – eg. 25 kilobytes per second of useful data
4. Roaming
ZigBee modules can be configured to work as a local repetitors
5. Free stack with API
Chipcon (Texas) developed a stack for its chips with well documented API, but I haven’t had a chance to play with it, but will soon 
Texas Instruments (chipcon) offers all in one built microcontrollers (with radio of course) for low price. All you need besides this chip is MAC and an antenna. But if ZigBee will be used in low range eg. 10 meters, it can use an on board antenna (antenna printed on PCB).
I had a privilege to obtain free set of development boards to keep me occupied during vacations (pic bellow):
Zigbee evalutation module
Tags: 802.15.4, Communications, Telecommunications, Wireless, Zigbee
