[mikeg8]

A call center is probably as opposite of blue collar as it gets. The term “blue collar” comes from the blue collards shirts factory and industrial workers used to wear, and is now synonymous with manual labor. There is nothing remotely close to manual labor at a call center. You just had the lowest tier of a white collar job.

[harvey9]

The similarity is around control of the workers time in a 'production line' fashion. (I have also worked in a factory on a line).

You're correct about the origin of the term now collar. In places where deindustrialization has cleared out most production jobs, call center work is one of the things that replaced them.