Philadelphia Ranked 7th Among Most Cursed Sports Cities In America. PHILADELPHIA - JUNE 09: The Chicago Blackhawks celebrate after defeating the Philadelphia Flyers 4-3 in overtime and win the Stanley Cup in Game Six of the 2010 NHL Stanley Cup Final at the Wachovia Center on June 9, 2010 in Philadelphia, Pennsylvania.
Duplex (telecommunications) - Half duplex. 1  A half-duplex (HDX) system provides communication in both directions, but only one direction at a time (not simultaneously).
Above: A telegraph register unit, made in Utica, NY by the Chubbuck Co. Above: A duplex key or double speed key, a device that has a contact on both sides of the key arm. In April, 2014 we received the following comment: The double speed key was invented and offered as an alternative to the straight key. Telegraphers using a straight key over a long period of time developed Carpal Tunnel syndrome. The double speed key was a SIDESWIPER and often referred to as a cootie key.