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.
On January 31, 2008 the US Navy tested a railgun that fired a shell at 10.64 MJ with a muzzle velocity of 2,520 m/s (8,270 ft/s). Its expected performance is a muzzle velocity over 5,800 m/s (19,000 ft/s), accurate enough to hit a 5-metre (16 ft) target over 200 nmi (370 km) away while firing at 10 shots per minute.