Panasonic KX-FLB852CX Service Manual page 191

KX-FLB852CX / KX-FLB852CXS
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: CN601 1pin
D+: CN601 2pin
D-: CN601 3pin
GND: CN601 4pin
Circuit Diagram
Sequence of normal operation
When USB cable from PC is connected to CN601, Vbus voltage goes up to 5V.
USBPWR becomes about 3V, and IC600 recognizes the connection with PC. Then D+ becomes about 3V: waveform 1
The D+ becomes 0V, then communication between IC 600 and PC is started: waveform 2
When a few seconds elapsed after USB cable was inserted into CN601, the unit enters stand-by mode.
When PC is at Full Speed, waveforms are 3 and 4.
When PC is at Hi-Speed, waveforms are 5 and 6.
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