-- first param is item #, second is line # (of global)
pass openCard
end openCard
-- part contents for background part 6
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27127
-- part contents for background part 24
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Carrier Sensing, Multiple Access (CSMA)
The “carrier” referred to is the signal on the cable.
When a device is ready to transmit, it will first check the cable to see if some other device is currently transmitting. In other words, it will try to sense another carrier on the cable.
Carrier sensing can be done at any time because the device just listens; it doesn’t interfere with messages being transmitted.