GSM modem giving echo after echo off command

Hai friends,
I am working on a GSM modem, which is SIM 300 command supported.
Everything was working fine, like I can send SMS, send data through gprs, etc.
At first, when I turn the modem to ON position, I am cancelling the echo from the command using ATE0.
But sometimes, after handling with gprs commands, my modem responds with the echo characters also.
This occurs, often when the modem gives a +PDP DEACT response. Unfortunately, I am not saving the current configuration of modem. My doubt is that, will the modem configuration changes without restarting the modem?

Also, usually the modem give responses as soon as it gets the command. But what is the maximum delay that the modem takes for a response?
Please help me.....

+PDP DEACT is an unsolicited response its not an echo. This comes with or without turning echo on. so you cant do anything for that.

different commands needs different delays.. commands that deal with network and SIM takes more time. incase of SIM300 most of commands they responds within 500ms and general commands they responds withing 100 to 200ms. for GPRS some commands need you to wait longer.. e.g AT+CIICR this command does not respond till connection is up. you cannot generalize timings but yes you can keep max timeouts for different types of command.

Hai Ajay,
Thank you for your reply.
I am running the modem using program written in pic.
Actually, Ithis is what happens when I restart the modem....

AT
>ATOK
ATE0
>OK

After this I am sending some AT commands related to gprs. And I am able to send data through gprs.
But sometimes, my modem hangs and then if I send commands, it gives the following response...

AT
>ATOK
ATE0
>OK

But finally, I think I am able to solve it by using the command
AT&W to save the configuration. I hope that works...Until now it's not echoing the charaters...
Thank you

ponnus, we have recently lost many forum posts during server migration. I have no idea about the last status of your problem. Do let us know if you still have any issues. Sorry for inconvenience.