nub101

Hi guys, I have a 2nd hand DVR and 2 cameras system ( DVR has a Spot port and Monitor port). I have installed the system with no problem @ home. But, I was wondering instead of having the pictire being displayed on the monitor. Can I somehow tap it into my home cable TV and display this on a channel on my TVs? I have see this work over @ my friends apt. building. What is it called, where can I buy it, and what are your recommendations? Tx