Tip And Ring
Tip and ring are the standard industry terms of the two wires or sides of a telephone line. They originate from the early days of telephone service when concentric plugs were used that had one wire connected to the plug tip and another to a ring on the shaft. When inserted into a socket, a telephone connector would first connect the grounded circuit side on the tip, followed by the active battery potential on the ring. In the UK, tip and ring are referred to as the 'A' (earth) and 'B' (battery) wires.
Tip has a potential of 0 volts with respect to ground, while the battery side carries a DC potential of −48V when in the on-hook (idle) state (nominally −50 volts in the UK).
Read more about Tip And Ring: Origin, Line Voltage, Polarity, Color Code
Famous quotes containing the words tip and/or ring:
“Panache upon panache, his tails deploy
Upward and outward, in green-vented forms,
His tip a drop of water full of storms.”
—Wallace Stevens (1879–1955)
“Time has no divisions to mark its passage, there is never a thunderstorm or blare of trumpets to announce the beginning of a new month or year. Even when a new century begins it is only we mortals who ring bells and fire off pistols.”
—Thomas Mann (1875–1955)