Send text over XBee API Interface to XBee Router AT


I’m pretty new to XBee so maybe my question is kind of dumb, but I did’nt find an answer to it on google…

I have two XBee Radios:
Radio 1: API connected to a RaspberryPi over USB
Radio 2: Router AT connected to a roomba

Both Radios are Series 2

My challenge:
I want to set AD0 on Radio 2 to high (so that the roomba knows, that commands will appear over the serial line) - This is easy to achieve with Radio 1 in API Mode.
But then i want to send commands from Radio 1 to Radio 2 (the perl-script found on the internet works great:

printf $roomba "%c",128;  sleep 0.3;

). If both radios are in AT, it works great - but as long as i can’t put the AD0 on Radio 2 it will not work without “human help” pushing the “On” Button on the roomba.

I did’nt found any command for the xbee-API to send text, or anything else…

I need to pull the AD0 on Radio 2 and I need to send text-messages to the roomba, so I’m in a situation, where I really need help to achieve my personal goal.

Thanks in advance for any help