XBEE Series 2 Co ordinator not responding if switched OFF and ON while transmitting

Hello All,
This is regarding XBEE series 2, i am using XBEE module with RS232 break out board . One device is configured as Co ordinator and other as an End device in point to point network. Suppose if co ordinator is transmitting and End device is receiving; and end device is switched OFF and ON , with application ( hyperterminal running). In this case the end device does not respond( means if i type at co ordinator end, nothing is received at end device hyperterminal after switching ON .
If i switch off and on the co ordinator ,the co ordinator does not respond.
Can somebody guide me? Thanks

I cant troubleshoot your problem but wanted to ask you problem that i am facing…

I have two modems and wanted to from peer to peer configuration network in bet them…

I am having Xbee series2 modem having 232 connection facility.
Modem type is XB24-B
firmware version is 1020

Can you please suggest how do i address these two? Firm ware should i use?