how do i send a character from 8051 to xbee series 2

how do i send a character from 8051 to xbee series 2 and receive through coordinator xbee. what must me the configuration settings

presently i am using both router and coordinator in AT mode.

when router is connected to PC the character typed is received by the coordinator but when i connect the router to MICROCONTROLLER it is unable to transmit. but i can see character is been received in route terminal screen (in XCTU software.)

Please do help me ASAP.

Thank you in Advance.

What is the 8051 device? How are you connecting an XBee to it? What voltage level is your 8051 device running at? Are you able to send data from that 8051 device to the PC direct?