Long periods of 0's will cause problems.

Short bursts of information like preamble,synch,address,data,checksum etc
work just fine. The payload is delivered just after everything is stable and in
synch. Even a few bytes of data with large numbers of 0's works, but you
wouldn't want to stuff 50 words in there made up of all 0's.

If you're transmitting long streams of serial data that can vary from all 0's
to all 1's, then you might want to look into using manchester.

Here's one example of how a simple remote control encoder works.
http://www.linxtechnologies.com/docu...datastruct.pdf