The DH-E20 is compact and slim, with a simple and symmetrical design that harmonizes with various modern buildings and can even be installed on narrow door frames. It is based on the SIP protocol and supports WIFI wireless access, solving the problem of protocol incompatibility. It can achieve efficient expansion and linkage with video phones, mobile apps, monitoring systems, third-party access control, etc., and is easy to operate and deployable. At the same time, its sizeable physical button design and large circular backlight design improve the convenience and comfort of the experience.