Viking entry phone controller and call router. Allows single line telephones or a telephone system to share a phone line with a door entry phone. House phones ring with C.O. line cadence or distinctive ring when the entry phone is calling. Built in five number dialer. Detects busy or ring no answer and goes onto the next number. Built in door strike relay with 1 or 2 digit commands. Detects touch tones as fast as 50 milliseconds. Postal lock input. Produces "Call Waiting" tones if the entry phone is activated when the house phones are already on a call. Add an entry phone to your standard home or office phones to provide door communication. Provide commercial or residential security via two-way handsfree communication at the door or gate. Connects in series with a single phone line or to a phone system's unused line input (loop start trunk input).