Panasonic KX-MB283BR Service Manual page 133

KX-MB283BR
USB (Universal Serial Bus) block
Description
This is a USB block for data communication with PC.
Two signal lines (D+/D-) are differential signals which work in reverse phase.
VBUS: CN300 1pin
D+: CN300 3pin
D-: CN300 2pin
GND: CN300 4pin
Circuit Diagram
Sequence of normal operation
When USB cable from PC is connected to CN300, VBUS voltage goes up to 5V, and IC300 recognize the connection with PC.
Then D+ becomes about 3V : waveform (1)-1
The D+ becomes 0V, then communication between IC300 and PC is started : waveform (2)-1
When a few seconds elapsed after USB cable was inserted into CN300 ,the unit enters stand-by mode.
When PC is at Hi-Speed , waveforms are (1)-1 ~ (1)-4.
When PC is at Full Speed ,waveforms are (2)-1 ~ (2)-4.
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