You are correct the Newgeat CM500 is my Modem, sorry. I attached that to the TRENDnet 4-Port Broadband Router TW100-S4W1CA. But it didn't work because only the modem has the place for the Coaxial cable to attach. 

For the last year it has been cable coming out of the wall, split into both the CM500 Modem and the Comact cable box which don't think I can use with the Trendnet box because no place to attach it. Comcast says must have cable box.

Any idea what I'm doing wrong:-)

I tried to use my Netgear Router which supported voice with a trendnet 4 port Ethernet broadband router, this didn't work because there was no way to connect my cable cord that comes out of the wall, slits into two. one was into my Netgear modem and one into comcast router but when I switched this to a Trendnet router I had no place for the cable in it.

Looking at your low wifi routers, I don't see a place there either for cable. 

Questions

1.How do I hook up the cable box when using these?

2. They don't support voice, correct?

Is it true that there can be an issue if my modem does not split the IP addresses. How do I know if the Netgear CM500V-100NAS Modem does?

Thanks So much