I’m trying to understand how an ISP could handle multiple concurrent calls on a single phone number? And did they need a physical modem for each connection? How did this scale to medium to large cities with millions of people? How did the call get transferred from copper wiring between the modem at home, to a modem in an exchange somewhere? What was that modem connected to? Did it vary between countries?
My naive understanding is that there is a direct connection (circuit) between the two modems, but I don’t understand how you could support two concurrent calls on one number.
In: 1
>I’m trying to understand how an ISP could handle multiple concurrent calls on a single phone number?
Phone companies offer a service to businesses that you can have one number for multiple lines. Nothing weird. Normal stuff. You actually will own like 2 or 10 or 10000 lines, but they all connect to the same number, and it “rolls over” to the next connection if one is in use. This is old and part of the normal phone system. Very large systems would often have a specific high capacity telephone line directly to them… or lots of these lines.
>did they need a physical modem for each connection? How did this scale to medium to large cities with millions of people?
In the earliest days, yes. There would be racks and racks of modem — however this changed with technology and ISPs were able to transition to some more complex software and hardware versions that didn’t require individual modems and was much much easier to scale.
> How did the call get transferred from copper wiring between the modem at home, to a modem in an exchange somewhere? What was that modem connected to?
It was done via the phone lines, later the phone lines connected to more complex networking centers which would allow more connections and easier access like above
Latest Answers