A:Answer Dear customer, for the Caller ID feature, you need to contact your service provider. If you already have it on a Cox line then it will work if you connected the base unit to VOIP providers' terminal. The following handsets are compatible with this model, for example (KX-): TGFA72(Included Handset); TGFA70; TGFA71; TGTA61; TGFA61; TGEA60; TGEA61.