Download Know Who is Calling Even if iPhone is Silent with Custom Vibration Alerts – Have you ever wished there was a way to know who was sending you a text or giving you a phone call when your iPhone is on silent mode, resting in your pocket or purse? You hear the buzz, but by default you?ll have no way to differentiate that from anyone else. It turns out there is a way to determine who is calling while the iPhone is on silent, and that?s achieved by creating and setting custom vibration alerts for contacts in a similar way as you can set unique ringtones or text tones for contacts. Set a Custom Vibration Alert for Individual Contacts – Open Contacts or the Phone app, and select a contact you wish to create a custom vibration alert for – Tap ?Edit? then locate the same section where you select unique ringtones and text tones, but tap ?Vibration? instead.