When either phone goes off-hook, the other phone rings and flashes (if it's a Batphone). Provides two seconds of dial tone and ring-back signal to the calling phone. Has standard RJ11 modular jacks. You can have up to 2.6 miles of 24-gage wire between phones. Even works with cordless phones. Requires electrical outlet. (Phones are not included.)
FREE "ground" shipping in the USA.
Ringdown Circuit connects two phones for intercom. FREE SHIP