The two most common RF radios that are available from Digi are the Series 1 and Series 2 XBee. The Series 1 and Series 2 modules are quite similar, but selection of a module should be based upon application specific needs.
All XBee radios have the same footprint and for the most part-are pin for pin compatible (with a few differences in the placement of ADC/IO lines), but are NOT interoperable. Series 1 and Series 2 use different application profiles, which are unique to each radio family. They can however, use the same RS232 or USB interface boards.
Product comparison specification Quick Facts for the non-pro variant of the two series:
XBee Series 1||
XBee Series 2|
up to 100 ft. (30m)||
up to 133 ft. (40m)|
Outdoor RF line-of-sight range||
up to 300 ft. (100m)||
up to 400 ft. (120m)|
Transmit Power Output||
1 mW (0dbm)||
2 mW (+3dbm)|
RF Data Rate||
-92dbm (1% PER)||
-98dbm (1% PER)|
2.8 - 3.4 V||
2.8 - 3.6 V|
Transmit Current (typical)||
45 mA (@ 3.3 V)||
40 mA (@ 3.3 V)|
Idle/Receive Current (typical)||
50 mA (@ 3.3 V)||
40 mA (@ 3.3 V)|
ISM 2.4 GHz||
ISM 2.4 GHz|
0.0960" x 1.087"||
0.0960" x 1.087"|
-40 to 85 C||
-40 to 85 C|
PCB, Integrated Whip, U.FL, RPSMA||
PCB, Integrated Whip, U.FL, RPSMA|
Point to point, Star, Mesh (with DigiMesh firmware)||
Point to point, Star, Mesh|
Number of Channels||
16 Direct Sequence Channels||
16 Direct Sequence Channels|
PAN ID, Channel & Source/Destination||
PAN ID, Channel & Source/Destination|
Since hardware specifications are similar, the differences between XBee Series 1 and 2 are more evident in the firmware features. Listed below are some of the more defining differences in the firmware:
802.15.4: XBee Series 1 comes standard with 802.15.4 firmware for point-point or star topology. This mature firmware offers ADC (analog-to-digital conversion) inputs, and digital and analog I/O line passing. The 802.15.4 XBee is significantly faster than ZigBee; RF latency can generally be calculated in 802.15.4. Throughput is also much higher, a practical maximum throughput is around 80kbps.
ZigBee: XBee Series 2 does not offer any 802.15.4-only firmware; it is always running the ZigBee mesh firmware. The ZigBee XBee excels in very low-power scenarios, when configured as an End Device, this module has the lowest current draw of any Digi RF product. However, the infrastructure of a ZigBee network is more complex and requires more configuration to fully impliment. The main benefit of a ZigBee XBee is third-party device support and deep integration with the Device Cloud by Etherios and Digi gateway products.
One unique benefit of the 802.15.4 Series 1 XBee is that it can have the DigiMesh firmware installed. DigiMesh is Digi proprietary mesh network protocol and is directly comparable to ZigBee. This allows a small network to be implemented as a Star topology, then later converted into a full mesh network without replacing hardware. A whitepaper comparing DigiMesh and ZigBee can be found here: http://www.digi.com/pdf/wp_zigbeevsdigimesh.pdf.
A study of the product manuals to compare the Series 1 and Series 2 radios more completely is left to the user. However, Digi Applications Engineers are available to discuss these differences in greater detail, and can be reached at 1-801-765-9885.