The KX-TD160 is a 2-Port Door Controller. It works with any KX-TD816 or KX-TD1232 regardless of the revision level. KX-TD1232 systems with Version 4 firmware and below will show “1234” in Program 607 and 608 (Doorphone Ringing Assignment – Day/Night) whether they are in a single cabinet configuration or a dual cabinet configuration. In the programming display screen, 1 & 2 represent the 2 doorphones on the Master cabinet and 3 & 4 represent the 2 doorphones on the Slave cabinet.