How to Use Blocking Rules

Set CallShield as Your Default Call Screening App

Before CallShield can block any calls, you must grant it the role of Default Call Screening App on your device. This is a critical one-time setup step that allows CallShield to intercept and evaluate incoming calls at the system level.

1. Open the CallShield app on your Android device.
2. On the Home screen, you will see a prominent red button labeled "SET AS DEFAULT SPAM APP".
3. Tap the button. A system dialog will appear asking you to confirm your choice.
4. Select CallShield and tap "Set as default".
5. The status indicator will change to a green "PROTECTION ACTIVE" message, confirming that CallShield is now actively screening your incoming calls.

Unknown Number Blocking

This is the simplest and most aggressive blocking mode. When enabled, it will automatically reject every incoming call from a phone number that is not saved in your device's contact list. This is extremely effective against random spam callers, cold-calling telemarketers, and automated robocall systems.

How to enable: Tap the "Unknown" card in the Block screen. You will see a toggle switch labeled "Block Unknown Numbers." Simply flip the switch to ON. All calls from unsaved numbers will now be silently rejected.

Best for: Users who primarily receive calls from known contacts and want maximum protection from strangers. Be aware that legitimate calls from new or unknown numbers (such as delivery drivers or doctors) will also be blocked while this is active.

Specific Number Blocking

This mode allows you to manually build a blacklist of specific phone numbers. Each number you add will be permanently blocked until you decide to remove it from the list. This is perfect for handling persistent callers who keep calling from the same number repeatedly.

How to add a number:

1. Tap the "Numbers" card in the Block screen.
2. Tap the "+" floating button in the bottom-right corner.
3. Enter the full phone number you wish to block (including country code if applicable).
4. Tap "Confirm" to add the number to your blacklist.

You can edit an existing number by tapping the pencil icon next to it, or delete it by tapping the trash icon.

Prefix Blocking PRO

Prefix blocking allows you to block all phone numbers that begin with a specific sequence of digits. This is an incredibly powerful tool for blocking entire area codes, country codes, or operator ranges at once, rather than adding individual numbers one by one.

How to add a prefix:

1. Tap the "Prefix" card in the Block screen.
2. Tap the "+" floating button.
3. Enter the prefix digits (e.g., +44, 021, or 0800).
4. Tap "Confirm" to activate the prefix rule.

Example: If you enter the prefix 0800, CallShield will block any incoming call from a number starting with 0800, such as 0800-123-4567, 0800-999-0000, etc.

Range Blocking PRO

Range blocking lets you define a start number and an end number. CallShield will then block every phone number that falls between those two values numerically. This is particularly useful for combating batches of spam numbers that use sequential or closely grouped phone numbers generated by automated dialing systems.

How to add a range:

1. Tap the "Range" card in the Block screen.
2. Tap the "+" floating button.
3. Enter the Starting Number (e.g., 08001000000).
4. Enter the Ending Number (e.g., 08001009999).
5. Tap "Confirm" to activate the range rule.

Contact Blocking

Sometimes you need to block calls from someone who is already saved in your contacts. Rather than deleting their contact information, CallShield allows you to select specific contacts to block while keeping their data intact in your phonebook. This is a discreet and convenient way to handle unwanted calls from known individuals.

How to block a contact:

1. Tap the "Contact" card in the Block screen.
2. Tap the "+" floating button.
3. A contact picker dialog will appear showing your saved contacts.
4. Select one or more contacts you wish to block.
5. Tap "Confirm" to add them to your blocked list.

Schedule Blocking PRO

Schedule blocking automates your call protection based on time. You can define specific time windows during which all incoming calls are automatically rejected. This is perfect for sleeping hours, focused work sessions, meetings, or any period where you do not want to be disturbed by any phone calls.

How to add a schedule:

1. Tap the "Schedule" card in the Block screen.
2. Tap the "+" floating button.
3. Enter a Label for your schedule (e.g., "Sleep Mode" or "Work Hours").
4. Set the Start Time (e.g., 22:00).
5. Set the End Time (e.g., 06:00).
6. Tap "Confirm" to activate the schedule.

Pro tip: You can create multiple schedules for different purposes. For example, one for sleep (10 PM – 6 AM) and another for daily meetings (2 PM – 3 PM).