TD12HB 12 CALL HANDSET INTERCOM MASTER UNIT - AIPHONE AIPHONE TD-12HBThe TD H Series is a multi channel selective call handsetintercom system. With five different call handsets, the system can be configured to meet most selective calling applications. Internal communication (multi talk paths possible) Max. 2 door stations per system with door release All zones or individual zone page, with or without talkback Mounts directly onto wall or desk using included screws Requires a 12 Volt D. C. 70mA power supply per station