Is it ok to split cable tv and internet on the same coax line?

I recently had Time Warner install cable TV and Internet service in my house. I asked the install tech if it was possible to split the coax at the wall so I could have the cable modem and set top box located at the same place in the house.

He declined my request saying that they only allow that in apartments and not residential houses.

My questions are:
1. Will there be any issues in splitting the coax and having both the modem and dvr operate off of the same line?
2. If it is possible, is there anything I have to consider when buying a splitter?

Thanks in advance, and I look forward to everyone's input on this.

Wolf - Thanks for the feedback on your experience. Quick follow up question: Do you have HD service with an hdtv tv, and if so did you notice any quality loss after splitting the signal?

Ha! The technician is lazy. You can actually ask your cable/internet service if it's the same provider to put the modem where you want it.

Check the modem connection and if you see a splitter then remove that splitter and use a coupler to connect the input wire and one leads to the TV, then use the splitter where you want your modem. It should have something like 130db RFI and -3.5 to -7 db on the output port like this one http://www.sears.com/shc/s/p_10153 [...] e+splitter notice the frequency and the db output? Connect your TV to one with higher frequency.

Some splitter like this one http://www.newegg.com/Product/Show [...] -%20Retail is not good quality.