NEC Univerge UM8000, Руководство по установке

Страница: 51 / 130

UM8000 Issue No. 1.0
Installation Manual 6 - 7
The connection for a DCE device uses the swapped line cord shown in Figure
6-7 CD-VM00 RS-232 Serial Cable (DCE) on page 6-7 .
5.2 USB Interface
The CD-VM00 provides two USB interfaces that are in full compliance with the
Universal Serial Bus Specification, Revision 2.0. The connections to the USB
interface are through a dual Type-A plug connector. Some possible USB
devices are the following:
P
USB Keyboard
P
USB Memory Device
Per the USB spec, each USB device must start up in a low power mode
drawing one unit (100mA) of current. The device may then request more power,
up to 5 unit loads. For the APSU application, current draw of greater than one
unit load per device shall not be allowed. To limit the current draw on the 5V
received from the backplane, a dual power switch, TI TPS2046A or equivalent,
shall be utilized to allow power enable control to the USB ports and to protect
against short circuit events. If it becomes necessary to connect a high power
USB device to the APSU, an externally powered USB hub could be inserted
between the APSU and the high power device.
5.3 VGA Display Interface
The APSU card provides a VGA display interface through a standard DB-15
connector. The AMD LX-800 Processor interfaces directly to the VGA
connector. The VESA standard pin-out shall be used. Per the VESA standard,
5V is required to be supplied to the connector in order to support the DDC I2C
communication channel to the monitor only when the monitor is in sleep mode.
When the monitor is not in sleep mode, 5V is provided by the monitor power
source.
On the APSU, 5V shall be provided to the VGA connector in a manner where it
can be removed from the connector via component depopulation to reduce
current draw on the 5V power supply should this feature not be needed.
Figure 6-7 CD-VM00 RS-232 Serial Cable (DCE)