Panasonic KX-TDA5193 4-Port Caller-ID Card Compatible with KX-TDA50G and KX-TDA50 Telephone Systems Each card activates Caller ID on 4 CO lines One card mounts on the KX-TDA5180 8 Port CO Line Card Caller ID service must be order from your Local/ Long Distance Provider Required to receive Caller ID information on Panasonic Display Phones