PassDial cydia tweak allows you to specify passwords (other than your unlock one), that instead of unlocking the device, call a specific number.
It can hold 5 phone numbers and passwords. If you are using Simple Passcode (4 digit password), than your PassDial passwords MUST be 4 digits.
NOTE: If you are using a password that is longer than 4 characters, than your password to unlock your device must not be a Simple Passcode (if you do not know what this is, then you should probably stick to 4 numbers).
Configure options from Settings.