GPRS sleep mode DTR issue

In order to put SIM900 into sleepmode , i tried the following as a part of a code:

[code] //Enabling sleep mode in SIM900
GPRS_Serial.println(“AT+CSCLK=1”); //Enable Sleep mode, slowclock

//D3 pin of Atmega used to drive DTR pin of SIM900
 pinMode(3, OUTPUT);

//Pull DTR high to put it into sleep
digitalWrite(3, HIGH);

delay(30000); // 30sec delay where the SIM will go to sleep

digitalWrite(3, LOW); //wake up SIM900
delay(100);// a minimim of 50msec is req[/code]

I had wire going from DTR on J11 connector to Arduino D3 to toggle DTR pin. I am using Softserial interface.

After the execution a few times, i cannot get any reponse to any AT commands and looks like GPRS board is not responding to basic AT commands anymore.

Anyone seen this before ?

Any ideas ?