Node discovery does't return desired response.

XBee & XBee Gateway
, , , ,
1

I have configured three XBee’s with each other.One of the XB-S2C (API) is configured as a Coordinator and another XB-S2C and XB-S2 (both AT) as End Devices.
They communicate with each other as normal, and I have no issue with the Communication part of it.
When I use the coordinator to transmit a ND packet in API mode, I receive a response from sometimes either one, or both and sometimes I do not receive any response.
When I transmit the packet, the end devices wake up every time but their response doesn’t show up on the coordinators UART terminal.

Coordinator:
CE=1
DH:DL=0
AP=1
SM=0
SN=1
ST=1388
SP=400

End Device (S2C and S2):
CE=0
DH:DL=Coordinators S\No.
AP=0
SM=5
SN=1
ST=1388
SP=400

2

This is because End Device was sleeping when ND command was transmitted.

Since there are just 3 devices in system, therefore there won’t be to many re-transmissions as well. And considering that Sleep Period is above 10 seconds, missing ND command from Coordinator frequency is no surprise to me.