Switched Network

The Basics

Facilities

Voice Circuits

Lines vs Trunks

NPA-NXX

ANI and ANI II Digits

DNIS

Equal Access

On-Net  vs  Off-Net

Virtual On-Net

Traffic Types

Trunk Groups

Feature Groups

Feature Group A

Feature Group B

Feature Group D

PICC and USFC

PBX

DID

Start-Signaling

Hunt Groups

Centrex

Service Codes (*69, *70, etc)

N11 Numbers (411, 911, etc)

500 Numbers

700 Numbers

Toll-Free