Plain old telephone service. For direct inward dialing service, the telephone company provides one or more trunk lines to the customer for connection to the customer's PBX, and allocates a range of telephone numbers to the customer. Calls to such numbers are forwarded to the customer's PBX via the trunks.
A railgun is an electrically powered electromagnetic projectile launcher based on similar principles to the homopolar motor. railgun consists of two parallel metal rails (hence the name) connected to an electrical power supply. When a conductive projectile is inserted between the rails (at the end connected to the power supply), it completes the circuit.
With Railgun. Railgun consists of two software components: the Listener and Sender. The Railgun Listener is installed at your web host on an origin server. It's a small piece of software that runs on a standard server and services requests from CloudFlare using the encrypted, binary Railgun protocol.ailgun uses a collection of techniques to accelerate and cache these previously uncacheable web pages so that even when the origin server must be consulted web pages are delivered quickly. And that even works for rapidly changing pages like news sites, or for personalized content.