GE
D
IRECTION
FQ091019, R
EVISION
2
V
IVID Q
N S
ERVICE
M
ANUAL
Chapter 5 - Components and Function (Theory)
5-37
5-7-2-8
USB Hub
The USB connection arrives from the BEP. The USB hub drives the following devices:
•
Keyboard controller
•
Two general-purpose ports
(current up to 600 mA per port, over-current limit should be used).
5-7-2-9
Power Interface
Power to the keyboard is provided via the BEP
keyboard connector.
Two different voltages are supplied to the keyboard:
1.) 3V standby for driving the power On/Off and status LEDs.
2.) 5V BE (Back End) is used for the remaining circuits.
The keyboard operates with
±
5% voltage deviation on each supply.
The keyboard has current-limiting circuitry (implemented on the BEP), to protect it against excessive
current consumption (via the USB and/or short circuits).
5-7-2-10
Keyboard ID
The keyboard PCB contains an EEPROM which stores a variety of information about the keyboard such
as, GE part number, manufacturing date, and revision # of the PCB hardware.
The EEPROM size is 1KB.
5-7-2-11
Keyboard Connectors
Figure 5-27 Keyboard Module Connectors
USB Input Control
and PS2 BUS
2 x USB Ports for
customer use
ECG Module Connection
