AT command inputting problem

[tariq7868]

Hello , i have sim300 gsm module,, i have connected its serial port to pc via simple 3-5V converter & max232 ,, the problem is that when i power on the module (with baud rate set to 115200) i get "Call ready" on HyperTerminal. The problem is when i input 'AT' i dont get 'OK' response ,,,& i have also checked on other terminal softwares such as MikroC's terminal & Advanced Serial Port Terminal,, but not getting any response...plz help me,,, Have already checked the level convertors ,whcih are alright...

 

[tariq7868]

i have used only tx & rx pins ,, & have grounded the rts pin