Skills And Expertise: "Phone system"

[judycrowellstyle]

I see a lot of jobs I'd like to consider auditioning for as a voiceover artist, but one of their job deliverables (besides "female," "american accent," "middle age," etc.) says "phone system." Can anyone tell me what that means? Do you have to be able to deliver a project to the client using a certain software program that makes it sound like you're on a phone? Thanks.