The MY value defines an address for an XBee. The DL value defines the address of the XBee that it will be talking to. An XBee can have only one DL address, so it can only talk to one other XBee.
Seems like a real problem, right? Well, there is one special DL value, 0, that means broadcast mode. Broadcast sends the data to all other XBees on the PAN.
A perfect solution, right? Just make every XBee transmit everything, and let the Arduinos sort it out. Well, no. There is a drawback to broadcast mode, and that it that broadcast messages are low priority. It can take a while to get a broadcast message sent.
The way to handle the paradox is to have the master use broadcast mode to request data from a specific Arduino. The master XBee broadcasts a request for data ("Hey, Joe, talk to me"). All the XBees get the request, and pass it on to the Arduinos. Only one Arduino knows that it is "Joe", so only it prepares a reply, and passes it to its XBee to send, directed to the Master's DL. The other Arduinos know that they are not "Joe", so they do nothing about the incoming request.
can every xbee handle this? or just series 1 or 2?