A:Answer I don't know, but the handset screen will let you know when you are out of range, so I had to turn around and go back. I didn't lose the connection, but I was warned. You can go online to ATT-----www.telephones.att.com/accessories------ and enter the model number- then scroll to the bottom of the FAQs page and send them your question, and they give a prompt reply. Remember that walls block signals. We do have excellent signals in the bedrooms. Phone #1 needs to be by the base next to the modem.