How to Lock and Unlock an MTNL Phone

By Mandy Slake

Mahanagar Telephone Nigam Limited is an Indian telephone company that allows subscribers to make standard trunk calls and international calls. Depending on the subscription, the phone may have both services or only standard trunk service. Either way, you can block the types of calls the phone can make and receive using a PIN. You can set or change the PIN from your MTNL phone.

Step 1

Dial "123 1111" on your MTNL phone, followed by a four-digit PIN number of your choosing.

Step 2

Listen for an acknowledgement tone on the receiver.

Step 3

Dial "124" followed by your PIN then "2" to block all incoming and outgoing calls. Dial "1" at the end instead to block all calls except for special numbers.

Step 4

Dial "124" followed by your PIN and "0" to unlock all calls if your phone MTNL phone has both subscriber trunk dialing and international dialing.

Step 5

Dial "124" followed by your PIN and "3" to unblock all calls if your phone only has subscriber trunk dialing.

Step 6

Dial "124" followed by your PIN and "4" to block all outgoing calls.

Step 7

Dial "124" and your PIN followed by "5" to block standard trunk calls on phones with international dialing and trunk dialing. This feature is not available on phones with trunk dialing only.

Step 8

Dial "124" followed by your PIN and "6" to block local and special calls. This feature is also not available on phones with trunk dialing only.

Tips & Warnings

  • Reset your PIN by dialing "123" followed by your current PIN, then your new PIN.