Custom vibration patterns can be added and assigned to a contact on Samsung Galaxy S4, S3. When that number calls you, the phone starts vibrating with the assigned vibration pattern.
In order to set a vibration pattern to a specific contact do as follows:
1. Open "Contacts" App
2. Tap on the name of the contact to add vibration pattern
3. Find "Vibration pattern" and tap on "Default"
4. The list of vibration patterns is shown
5. Select from the list of available patterns
6. Tap on "Create" to make your own pattern. See: How to Create Custom Vibration on Galaxy S4
7. Save the process after done
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