An IP phone does not climb, it goes sideways 🐧

Doing operations for phone lines, there is something I learned.

These days there are 2 kinds of phone: the normal phone and the IP phone.

For a normal phone, the area code at the front of the number decides where it goes. In Nagoya, where I live, numbers mostly look like 052-xxx-xxxx, and in Tokyo I think they look like 03-xxxx-xxxx.

It looks at that first number, like: customers on 052 are over here in Nagoya, customers on 03 are roughly Tokyo and the area around it. So it climbs up to the equipment above first, and then branches down into finer and finer parts.

But roughly speaking, an IP phone works at the layer 3 level, so it does not need to climb up to ask which city area this is. It can just go sideways, on and on.

So it does not need the processing on the upper equipment, which is handy.

With a normal phone, the equipment at the very top that handles 052 or 03 has to be a machine with a lot of clever processing in it.