RSYNC New Requires a PORT

I see lots of emails where folks have requested a different port for rsync backup and it looks like a change has been made to require manual port entry for a new backup job.  The problem is that none of the documentation out there tells which port to use.   I'm a casual user who tends to follow the documentation when setting up things....   I see port 22 mentioned a bit but I get an error trying to set it up.  So, it's all great taht we can use whatever port we want, but what is the standard port that worked fine for me in the past?