In the mid '80s I was a telemarketer for a company that manufactured restriction and modifying enzymes. The most important part of my job was to find the right contacts and engage them.
Question #1 was "Do you have time to talk?"
If the answer was no I said "What would be a convenient time to call back?"
I entered that in my Dbase program and called them back when asked. After a few pleasant and punctual call backs they usually listened to my pitch.
I simply needed to let them know who we were and that we wanted their business. If they got technical I asked them to hold, I would see if the VP in charge of production was available and if not - get a good time for him to call back.
My job was making contacts..
The contacts that stood out were the guy that told me how he was going to catch rapists using DNA and the woman that was supervising hundreds of strains of genetically modified corn.
A lot has changed since then, but in marketing the basics are still the most important.