<prompt> tafadhali geuza maudhui haya ya swahili kwenda kwa kiingereza.swichi za msalaba ziliwekwa kwa mara ya kwanza katikati ya karne ya 20 huko sweden, merika, canada, na great britain, na hizi zikaenea haraka ulimwenguni kote.  <response>: crossbar switches were being first greatly mounted in the middle twentieth century in click here sweden, the us, canada, and great britain, and these rapidly spread to the remainder of the earth. 