As explained in section 12.0 of the manual. The “LOCK” feature is turned "OFF" as a factory default setting.
If your T-Lock's
LCD displays "LOCK", then lift-off handset and input *123456# (star key, then 1 2 3 4 5 6 then the pound key) to unlock (e.g. turn "OFF" the lock function), and
enable all T-Lock's functions. Note: Make sure you have a working handset connected to the PHONE socket on the Call Blocker.
To Lock it, you may lift-off handset and input *000111# to turn "ON" the LOCK feature and LOCK all functions (LCD displays "LOCK").
If you continue with issues, please contact us.