Panasonic KX-TGP500 SIP DECT Phone System The SIP Cordless Phone System expands up to 6 additional TPA50 handsets. Support for up to 8 SIP registrations The KX-TGP500 SIP Cordless Phone System allows you to have up to eight (8) phone numbers 2.1" Large LCD with white back light on cordless handset Support for 3 simultaneous network conversations