You will be sent a skill-test tape before you even have a chance to interview. Before being hired, you will take a written English and grammar test, and you will be given a live skill test. Your steno notes from the skill test will be reviewed instead of, or in addition to, the translation. When you do get hired, don't expect to start off with all the plum assignments. A television news reporter doesn't get assigned to a presidential press conference the first day on the job, so don't expect to caption one on your first day on the job.
Certification is a thorny issue.
On the one hand, well-respected captioners and owners of captioning firms tell me that court reporting certification is largely inapplicable to the captioning field. To secure an RPR or RMR requires passing written tests on American law, as well as verbatim writing skills with legal material. The certification does not test for even a rudimentary knowledge of captioning technology or skill. Most captioners I've spoken to agree with this. A captioner's daily work is more difficult and more demanding than the CRR exam.