Broadcast problem

I’m having some problems broadcasting long data streams from the coordinator.

I use two PCs, one with a coordinator and the other with an end device. Both running hyperterminal. Modules in transparent mode.

I observed the data flow from the PC to the coordinator is interrupted by means of CTS line after a few thenths. Then there is a delay of a couple of seconds, again data, again a delay, and so on… Also sometimes the data received is corrupted.

When I do not broadcast the info, but sending it to the address of the end-device, the transmission is fast and never fails.

I search the forum and observed some people had the problem with the delays but no one mentioned the corrupted data… I want to send broadcast data but I see it is not reliable… Any ideas on why this happens??


I don’t think this is the right forum for your question, as you’re talking about “coordinator” and “end node”. Please reply with the product that you have and what type of firmware runs on it so I can move it to the proper forum to get a reply.


Excessive broadcasting is not recommended for ZNet or ZB. When a device sends a single broadcast, it buffers the data and enters information about the broadcast into a broadcast table to track it for 8 seconds. This information is stored so the device can rebroadcast each transmission 3 times. If the broadcast table is full (8 entries) and additional broadcasts are received, they are dropped (potential loss of data).

Broadcasting is further complicated when sending to end devices. Since end devices poll for data, the parent buffers the most recently received broadcast. It will send the broadcast to its end device children when they wake and poll for data. If multiple broadcasts are received quickly one after the other, end devices could completely miss all but the last, depending on when they poll.

To summarize the above, broadcasts should be used sparingly.

Sorry, it’s first time for me and I wanted to post to drop-in networking forum, since I’m talking about zigbee modules.

I can’t ckeck the firmware versions right now since I’m not at work, but I will add that info as soon as I can.


Thanks damon,

It makes sense for me now…