Are you using the XCTU version 5110 (the beta release)? I was using 5.1.0, which could have been the problem, since the beta version allows for 'over the air' config. I'm asking because the ftp from digi.com is down so I can't dl 5110.

I figured the easiest way to get RSSI is by entering the Xbee's AT command mode- it sends back a hex value of the actual loss in dB/m. I can enter this mode in HT pretty easily by entering '+++' and then the command 'ATDB', then exiting by the command 'ATCN' (or waiting 3 seconds for the timeout). However, I'm trying to do this with the firmware onboard, but I can't seem to figure out how to make it work..I made a new case and do the following:  
 
     case 'O':      //Get RSSI info
                 delayUs(100000); //No commands for 1/10 second to enter AT mode
                 uart0SendString((unsigned char *)"+++");
                 delayUs(50000);      //Delay 1/2 sec to get into AT mode
                 uart0SendString((unsigned char *)"ATDB");      //Command to get RSSI info, in db/m
                 uart0SendChar((unsigned char *)"\n");            //Press enter
                 rssi= uart0GetCh();      //Get first number, in hex
                 rssi2=uart0GetCh();      //Get second number, in hex
                 uart0SendString((unsigned char *)"ATCN"); //Exit AT mode
                 delayUs(100000);      //Delay 1/10 sec to get out of AT mode
                 uart0SendChar((unsigned char *)rssi);
                 uart0SendChar((unsigned char *)rssi2);
                 uart0SendChar((unsigned char *)" dB/m");
                 break;
 
But this doesn't seem to work: the string '+++' is displayed on the HT instead of making the Xbee go into AT mode. I also tried doing separate uart0SendChar((unsigned char *)"+") 3 different times, but got the same results..Any ideas?

I finally got the RSSI info from the AT mode! I made a new case in the main.c and called this function (which I put in the utils.c file). The 'ATCN' part is commented out because I'm still trying to get the timing to work correctly. However, there is a ten second time-out (which you can modify using the AT command ATCT), so it will return to transparent mode.  
 
unsigned char ATmode() {
 
     unsigned char a, b, c, d;
     unsigned char aconv;
     unsigned char bconv;
     unsigned char result;
     
     uart0SendChar('+');
     delayUs(200000);  //delay 2/10 sec to simulate user entry
     uart0SendChar('+');
     delayUs(200000);  //delay 2/10 sec to simulate user entry
     uart0SendChar('+');
     delayUs(200000);  //delay 2/10 sec to simulate user entry
     a= uart0GetCh();
     b= uart0GetCh();
 
     if (a=='O' && b=='K')      //If AT mode is entered:
     {
 
           delayUs(1000000);      //Xbee protocol- no characters sent for 1 second
 
           uart0SendChar(0x41);      //A
           delayUs(200000);
           uart0SendChar(0x54);      //T
           delayUs(200000);
           uart0SendChar(0x44);      //D
           delayUs(200000);
           uart0SendChar(0x42);      //B
           delayUs(200000);
           uart0SendChar('\r');      //ENTER
           delayUs(200000);
           a= uart0GetCh();      //First char sent is a new line
           a= uart0GetCh();
           b= uart0GetCh();
     }
     
           /*Exit AT mode
           uart0SendChar('0x41');      //A            
           delayUs(200000);
           uart0SendChar('0x54');      //T
           delayUs(200000);
           uart0SendChar('0x43');      //C
           delayUs(200000);
           uart0SendChar('0x4E');      //N
           delayUs(200000);
           uart0SendChar('\r');
           delayUs(300000);*/
           
 
 
     if (a>0x2F && a<0x3A)
     {
           aconv= a-0x30;      //Convert number from ascii to hex equivilant
     }
     
     if (a>0x40 && a<47)
 
     {
           aconv= a-0x31;      //Convert letter A-F to hex equivilant
     }
 
     if (b>0x2F && b<0x3A)
     {
           bconv= b-0x30;
     }
     
     if (b>0x40 && b<47)
 
     {
           bconv= b-0x31;
     }
 
           result= aconv*0x10 + bconv;            //Convert ab to hex number, return result
           
           return result;      
}