Of course it means nothing of the kind. A network guarantee means the same thing. If your call mysteriously hangs up then the telephone company guarantees that you can try dialing again to get a new call. Most network-savvy computer users have autodialing scripts that automatically redial, so when the line goes down all they notice is a brief pause while it reconnects. Many people have disagreed with my comment that telephone calls often spontaneously hang up.
Many people have an impression that telephone calls are, on the whole, pretty reliable.
This is true for short calls. If you make a three minute voice call, or a thirty minute voice call, then the chance of you experiencing a failure of the telephone system during that time is quite small. However, think how long your office computer has been connected to the Ethernet. It's probably more like months or years. If you try to keep a telephone connection active for months or years you'll pretty quickly realize that it's hopelessly unreliable compared to computer networking technologies like Ethernet.