You are here: PRODUCTS / Entry phone / AT 21 AT 21 Possible to adjust receiver volume. Choose from three ringtones. For example, one ringtone may be a call from the entrance, another might be the doorbell and the third some other suitable external equipment. AT 21 is fitted with a hearing loop. Features and advantages Hard-wired doorbell intercom for indoor use. Adjustable earpiece volume. Adjustable ringtone, volume and tune. Can also be used as doorbell – different ringtone. Supports hearing loop. Output for activating external equipment when ringing. Up to 999 doorbell intercoms in each system. Simple opening function. For connection to loop or star networks. Get in touch and we will help you! Get contacts Similar products Ringa 1707Access control, digital tenant register and entry phone i… Titta 1200Video camera for Ringa entry phones Titta SmartphoneEntry phone via mobile phone.