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Manufacturing support
Interoperability with other EM250 devices
The XBee module can interoperate with other EM250-based devices. The following should be
considered when communicating between a Digi XBee module and another EM250-based device.
The XBee firmware inserts 8 bytes at the beginning of the data payload that represent the 64-bit
address of the source module. Custom devices that transmit to an XBee or receive data from an XBee
should make provisions to manage these 8 address bytes in the payload. Data packets destined for
an XBee module should include the source address of the sending device with the most significant
byte copied first.
Crosstalk issue
The EM250 suffers from a crosstalk issue where data received on a channel that is 12 channels above
or below the current channel appears to be received on the current channel. RF data is detected on
the erroneous channel only if the signal level of the received RF data is around - 30dBm (XBee devices
separated by a few feet). For example, RF traffic on channel 0x0B could be seen on channels 0x0B and
0x17 if its detected signal level is around -30dBm. This could result in routers or end devices joining a
PAN, but reporting an incorrect channel.
The problem can best be avoided by setting the SC (scan channels) bitmask to only include 12
continuous channels. If SC is left at its default value (0x1FFE), the crosstalk issue will never occur.
Customizing XBee default parameters
Once module parameters are determined, Digi can manufacture modules with specific customer-
defined configurations. These custom configurations can lock in a firmware version or set command
values when the modules are manufactured, eliminating the need for customers to adjust module
parameters on arrival. Contact Digi to create a custom configuration.
XBee ZNet 2.5 / XBee PRO Znet 2.5 OEM RF Modules Product Manual
Interoperability with other EM250 devices
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