The KX-TD161 is a 4-Port Door Controller. It works with any KX-TD816 or KX-TD1232 v5 or higher. If a KX-TD161 card is installed in a KX-TD816 or KX-TD1232 V4 or lower, it simply will not work – even the first 2 ports. The controller just acts as if it’s dead. KX-TD1232 systems with Version 5 firmware and below will show “12345678” 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, 3 & 4 represent the 4 doorphones on the Master cabinet and 5, 6, 7 & 8 represent the 4 doorphones on the Slave cabinet.