A:AnswerHonestly I would double check this with the Geek Squad guys because some phones that I have had in the past did not work well with different brand/models.
A:AnswerAre you trying to register a CS6609-16 Accessory Handset to a CS6619-16 base? After charging the CS6609-16, place it in the cradle of the CS6619 base. Soon, registration will take place. VTech tech support: 1-800-595-9511.
A:AnswerShay - Conferencing with two outside lines is a network feature, so you'll need to contact your service provider. You typically use the FLASH feature of the phone.