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.
By passing current through busbars and projectile, a force is induced which propels the projectile along the bus-bars and into flight. In 1944, during World War II, Joachim Haensler hÃ¤nsler Of'germany S Ordnance office built the first working, railgun and an electric-anti aircraft gun was. proposed