Why the phone sometimes hangs by not echoing back transmitted data via AT commands?

[neoaspilet11]

Hi,


Why is it that the phone sometimes enetrs into hang state by not echoing back the transmitted data vi AT commands. However sometimes the phone successfully executed soem series of at commands.


Commands are transmittted via simulated microcontroller not on a hyperterminal


I put a 400 msec delay before sending anaother AT command.


Any idea would be highly appreciated.


Thanks