install immediately with xfinity -- very easy . but then I go to plug in the phone line -- oops ! my fault not theirs -- just think you would like to know . Amazon as always a simple return and buy a modem ` with telephony '' from Arris -- also through Amazon . up and work after a couple call to Comcast -- now do with the $ 7\/month rental fee -- do not ask how long I have be pay that !!!