My XBee Pro Series 2 won't communicate with my XBee S2C

I tried the S2C to S2 communication (My S2 module is a XBee Pro Series 2 XB24-ZB, set up with Router AT firmware), the 2 XBees didn’t communicate. I set the same PAN ID, set the S2C to Coordinator Mode, AP to Transparent, DL to FFFF, on the S2, JV is set to Enabled, DL to 0. I set 2 S2 modules on the XBee Shield (Arduino)

Is this an S2B, or a really old S2 only?

Not sure a really old Xbee can ever talk to a new one. I think I discarded all of my older pre-S2B years ago (I had some from 2007!)

But if an S2B, do make sure both nodes have the latest firmware, because an S2B with older/original firmware will NOT talk to any S2C at all. If memory serves me, an early version of the S2C firmware also could not talk to some S2B.

The latest firmware on both should allow them to communicate. We use S2C on our end-devices, and have many routers/coordinators with S2B. FW was the only issue we had to deal with.

It says “XBee Pro Series 2”. I configured them to Unicast mode and they can now communicate with each other. But then I tried to send a random short message through serial (Arduino), “Hello” for example, if I set the delay value small (less than 2 seconds) the message comes very slow and always arrive in bulk (10 messages after like 10 seconds to 15 seconds?), if the delay amount is too small (200ms) the message won’t arrive at all and if I set the delay to exactly 2 seconds the message arrives in real time. What is causing this horrendous delay? I thought the ZigBee communication method supposed to be very fast?

Is the S2C running ZigBee firmware? There are several different firmware loads for the S2C, and only one of them is for ZigBee.

S2C’s firmware is ZigBee TH Reg and S2 Pro’s firmware is ZigBee Router AT. I set them to Unicast mode and they can finally communicate with each other, but upon sending some serial messages through Arduino I found that if I set the delays between message too fast (less than a second), the message would arrive in bulk or wouldn’t arrive on the receiver at all. For short, it’s painfully slow. I used 2 S2C models on the Arduino XBee v1.1 Shield and the same thing happens, painfully slow connections. Currently sending messages from the Router to Coordinator. Really appreciate it if you have a fix. Thanks for your reply!

That sounds like an issue with the Arduino code, if you connected the XBees to a serial console you would find that you can send data much faster than once per second.

I tried connecting the XBee through a FTDI XBee USB Adapter and sending serial data through the Arduino and the message indeed sends much faster. But if I connect the router XBee to the Arduino shield (0,1 pin for RX/TX) sending a simple message and the coordinator XBee to the XBee USB Adapter connected to the Arduino (2,3 pin SoftwareSerial), tried parsing the message from the 2,3 pin to print on the 0,1 UART on the same PC, it doesn’t print anything! Is it because I’m plugging the 2 Arduinos and using the same UART to send/print the message?