I have cable via a cable jack in the wall NOT a converter box. I have a vcr hooked up now and I want to add a separate dvd recorder. How do I add/hookup the dvd recorder so that I can still record with both the vcr and the new dvd? I need to be able to use the timer recording feature on both devices. It is set up now as follows: Cable jack to vcr, vcr to TV. Thanks very much!!

This should work for you:
Cable Jack to DVD Recorder (Input)
DVD Recorder (Output) to VCR (Input)
VCR (Output) to TV

The DVD Recorder will be able to record, and should pass the signal along to the VCR so it can record as well. Only thing you may need to check is to make sure both are set for the same TV channel (CH3 or CH4 usually), and need to make sure the DVD Recorder passes the signal if it's on and off both. I know my VCR only passes it properly if it's on, but it needs to be off to record or something silly, so I had to make sure it was last in the signal chain.