Can telemarketers be classified in tax as independent contractors?

You really didn't provide enough information to help me answer the question that you posed. What kinds of codes are you speaking of?

Generally, whether a worker is an independent contractor or an employee is a question of Federal law - not state law - so it will be the same all over the USA. If the telemarketer controls the time, place and manner of her work, she's an IC, if the company controls the time, place and manner of her work she's an employee. For example, does the company require that she works from 9-5, does the company supply her with a desk, a chair, a computer, does the company give her a script she's required to read to prospects and she's required to make 50 calls a day. That's an employee. If the company says: here's our product for every one you sell we'll give you $10. She makes calls from her home, if she feels like working hard she can make 100 calls or if she's lazy that day she can make 10. She uses in own equipment. That's an IC.