Cell phone texting can be a huge deal for staying connected for teens who are Deaf  or Hard of Hearing. This cell phone sensor is activated when a mobile phone or tablet screen lights up, for example from an incoming call or message. Place it on top of the mobile device and connect it to the Visit system to be alerted with sound, flashes or vibrations when someone is trying to reach you. Available in two models: BE9250 for external trigger inputs and BE9251 for mobile phone sensor inputs. https://www.amazon.com/Bellman-and-Symfon-Phone-Sensor/dp/B00K57TWPC