I have a single cable enter my home , that Comcast install . for at least a year I be able to use a cheap passive 2-way splitter and watch both my tv thru a TiVo Premiere , and access the internet at 25mbp -lrb- nice -rrb- . but recently , for a unknown reason , the Internet Signal become too weak to access the web . the TiVo continue to work , as apparently it do not require as strong a signal . if I remove the Splitter , and connect the cable directly to my Cable Modem , the internet would work . but I want to watch tv , too ! every call to Comcast end with they want to send a technician over - while charge I $ 50 for the house call . although I have have skilled and professional Comcast Techs over in the past , I have find the majority do nothing but turn my Cable Modem on and off , and usually leave with no solution . so I proceed to eliminate the obvious . I inspect the Cable outside my home . it look in excellent shape , physically . indoors , I swap splitter . I swap Cables . no improvement . but by search the internet , I finally learn something new : I could check the signal strength myself , with equipment I already own ! my TiVo Premiere , and probably every dvr , have a sub-menu that will display signal strength . I discover mine be 67 . on a scale up to 100 , 67 be not good . and my Zoom 5341 Cable Modem -lrb- very recent and DOCSIS 3.0 -rrb- have a signal strength display as well . I expect pretty much any Cable Modem will have this function . just open m Explorer , type in 192.168.100.1 as a address , and you 'll be take to the access page . log in , and on a sub-menu the signal strength will be display . Mine be in the -5.5 to -6.5 range , on all channel . awful . so I purchase and install the bda-s4 . the signal strength on TiVo leap from 67 to 89 ! nice . but the Cable Modem be report no signal at all - Zero . I call Comcast again , and arm with this knowledge , emphasize how bad my signal strength be , for both device . the tech on the phone be impressed I could read the signal . for the first time I feel in control . he try to fix it , run I through the usual turn-it-on turn-it-off reboot drill , to no effect . each time I check the signal and tell he how poor the signal be . at last he say he need to talk to another tech - and simply disappear . he do not hang up on I , but must have be go for 30 minute or more . I never speak to he again . but what do happen , be quite suddenly the internet work ! my signal have increase from -6.0 to +6.0 . very nice . clearly Comcast do something , at they home office , that correct my signal . no tech need to visit at all . I be still use my bda-s4 , though ultimately I probably do not need it . it look to be very well make , and effective . Bottom Line : before you purchase any amplifier , check the signal strength yourself . you dvr and you Cable Modem should have this function already , you just need to know where to look . good Luck !