"One savvy Reddit user seems to think so! Also: hoards of other disgruntled and/or confused customers, according to Google. The scam? Charter's convincing customers that their perfectly good router hardware—including the Linksys WRT54G—just doesn't work with the ISP.
As reported by ZachSka87: I use a LinkSys router. I've had it set up and working perfectly for over a year. Well, the past few months, we've had several disconnects from Charter. We're paying for 10mbps service, but for the past week straight it would not go above 2mbps, and that's if it worked at all. We called Charter, and they had us plug the modem directly into the machine and Voila! over 20mbps speeds!" source