Panasonic KX-TDA0172 16-Port Digital Extension Card 16 Digital Station Ports Compatibility: COMPATIBILITY Panasonic Digital Phones such as the KX-DT300, KX-T7600, and KX-T700 Series Phones and DSS Consoles Panasonic Voicemail Systems such as the KX-TVA50 and KX-TVA200 Panasonic Wireless Cell Station Systems 2.4GHz Wireless 2-Channel Cell Station (KX-T0151) with KX-TD7684, KX-TD7690, and KX-TD7694 Wireless Phones Panasonic KX-TDA Series: KX-TDA100, KX-TDA200, and KX-TDA600 Panasonic KX-TDE Series: KX-TDE100, KX-TDE200, and KX-TDE600 Requires (1) free slot