SxS refers to the electromechanical circuit switches that improved on earlier manual cordboards. The SxS switch was invented and patented in 1891 by Almon B. Strowger, a Kansas City undertaker frustrated with the behavior of the local telephone company operator.According to legend, the operator was directing Mr. Strowger's incoming calls to a competing undertaker, who also happened to be her husband. Strowger responded by inventing an automated system that served 99 subscribers.The telephones that worked with that first automatic switch had two buttons. In order to reach subscriber 99, for example, the caller slowly and deliberately pressed the first button nine times and then the second button nine times. As the caller pressed a button, it completed an electrical circuit and as the caller released the button, it broke the circuit. Making and breaking the circuit caused a mechanical wiper, or selector, to rotate from one switch contact to another.As the user dialed each digit in the telephone number, the wiper would step up to the next level, step-by-step. Strowger's SxS patent served as the cornerstone for the company he founded,Automatic Electric Company, which later became the manufacturing subsidiary of General Telephone and Electric (GTE), but was sold to AT&T in 1989 to form part of AT&T Technologies. In 1996, AT&T spun that company off to form Lucent, which was sold to Alcatel (France) in 2006. GTE is now part of Verizon. SxS technology was considered state of the art until the appearance of the crossbar (Xbar) switch in 1938. Large numbers of SxS switches remained in service into the 1970s and even 1980s, and some likely remain in service to this day. See also cordboard, panel switch, and Xbar.