Panasonic KX-TDA0181 16-Port Analog Trunk Card LCOT1616-Port Loop Start CO Trunk Card (LCOT16)4 power failure transfer portsRequires 1 free slotAdd up to 2 optional 8-port Caller ID cards (TDA0193) for Caller ID supportUse with KX-TDA100, KX-TDA200, KX-TDE100, KX-TDE200 and KX-TDE600 systems..