How do you locate your mobile phone if the ringer is off? Maybe you switched the phone to vibrate mode while you were in a meeting and the device is nowhere to be found.

Wouldn’t it be nice if you could borrow your colleague’s phone and use it to turn on the ringer of your missing phone?

Meet Agastya, a new Android app that lets you “remotely” perform various tasks on your phone from any other phone via simple SMS commands. The other phone, that is sending the commands, need not be running Android - even the basic Nokia 1100 would do just fine - and either phones don’t require GPS or data plans (Internet).

The workflow is easy. You send an SMS command from a friend’s phone to your own phone in a given format and the app reacts accordingly. For instance, a command like “ringer” would turn on the ringer while “silent” would put the phone to silent mode.

The app can also help you retrieve your missed calls list or your incoming text messages via, you got it right, SMS. This feature should be handy for people who own multiple phones – you can easily check the call and SMS logs of your secondary phone from the one that’s in your pocket.

Here’s a complete list of SMS commands that you can try on your Android phone:

• SILENT – Turn off the phone’s ringer
• RINGER – Turn on the ringer
• IMEI – Get the IMEI number* of your phone
• LAST MESSAGES – Retrieve the last 5 text messages received on your phone
• LAST CALLS – Know the last 5 missed/received/dialed numbers
• CONTACT – Fetch the contact number of a person from the address book.

PS:The IMEI number can help you block a misplaced (or stolen) phone from accessing mobile networks (type *#06# to know the IMEI of your existing phone).

Agastay isn’t the first app that offers such features. The more popular Where’s My Droid app can not only turn on the ringer of your phone remotely but will also send you the phone’s current GPS location by SMS. There’s overlap but these apps are more inclined towards locating your lost phone while Agastay is like a command console – you can toggle between phone states or even fetch details of a contact remotely from the phone’s address book. The IMEI feature is also handy for blacklisting your misplaced phone.

In my tests, Agastya did work as advertised and the SMS based commands executed almost instantly though the app did crash in one instance. The company says that Agastay works on Android 2.2 and above.

On a related note, if you aren’t allowed to carry cell phones in your office, you should grab the SMS to Gmail app as it will auto-forward all your incoming text messages and missed calls list to your work email address.

Also see: Remote Control your PC with SMS Commands