The DS-KAD709 by Hikvision is an integrated unit that supports two-wire indoor and door stations. It is compact, convenient, and easy to install. Its two-wire interfaces and adaptive network interface can support up to nine devices, and one external switch.
Two-Wire Video/Audio Distributor
Nine Two-Wire Interfaces, which Support Nine Two-Wire Indoor Stations
One 10/100M Self-Adaptive Network Interface to Support External Switch
Industrial Design and DIN Rail Mount Supported
24 VDC Power Supply and Communications between Door Stations and Indoor Station