2-Wire Intercoms - Wiring for new and existing systems - Cornick
2nd Generation Intercom Home Page
SA&J 2-Wire Intercom/Tally Breakout Cable For Hitachi CCU | DB25F-23XM/3XF/3XX-2W/P1/TRG-H1-XX*
Hollyland 2/4 Wire Converter for Intercom HL-2/4 WIRE CONVERTER
Two-wire IP video intercom - Securevive
2 Wire Intercom Indoor Station
Amazon.com: 1byone Video Door Phone Intercom System Doorbell Kit, 2-Wire for Easy Installation with 49ft Cable, Control 2 Locks, Night Vision HD Camera and 7-inch Color Monitors : Electronics