I don't work with the phone public, I administer a corporate telephone system with offices across the US. I've worked on traditional telephone systems and we're now on a VoIP (Voice over IP), which is voice over the data network like Comcast Voice. Someone in our Washington DC office can pick up a phone, dial a 4 digit extension, and reach someone in our California office.
I install and configure telephones, voicemail, Call Centers, call accounting systems, telephone circuits, audio conferencing, etc.
I could never work on a phone myself, taking and making calls to customers. I am behind the scenes making sure the phones work for those who do.