Honestly, about the only thing that would cause specifically what he suggested: the pair was reversed at the CO.
Yes, I would hope it's been fixed by now. :p I replied mostly because there is too much misunderstanding in this field. I know few people in VoIP, or in the carriers who actually know how it works end-to-end.
I probably know more about transport than most of the techs in the world. I used to be one of those guys carriers would come to in order to resolve transport issues their own people couldn't figure out, from DS0 to OC-192. I am fully trained and comfortable with virtually every piece of switch-gear and endpoint you will find in a large CO, as well as every application behind it, and alarm system. I own my own TestPAD 2209 for DS1 and DS3 testing and qualification. Any field tech, ops person, or telecom analyst who professes to know ATM transport and yet has never worked with a test-set (more than just being familiar with the buttons), isn't worth a hill of beans.
I've come down from the cloud and use this knowledge privately and for much higher-paying employers now.
