Usb Cable Data - HP Compaq dc7900 USDT Technical Reference Manual

Input/Output Interfaces
Pin Signal
1 Vcc
2 USB-

5.7.2 USB Cable Data

The recommended cable length between the host and the USB device should be no longer than
sixteen feet for full-channel (12 MB/s) operation, depending on cable specification (see
following table).
Conductor Size
20 AWG
22 AWG
24 AWG
26 AWG
28 AWG
NOTE:
For sub-channel (1.5 MB/s) operation and/or when using sub-standard cable shorter lengths may be
allowable and/or necessary.
The shield, chassis ground, and power ground should be tied together at the host end but left
unconnected at the device end to avoid ground loops.
Signal
Data +
Data -
Vcc
Ground
5-12
Table 5-8.
USB Connector Pinout
Description
+5 VDC
Data (minus)
Table 5-9.
USB Cable Length Data
Resistance
0.036 Ω
0.057 Ω
0.091 Ω
0.145 Ω
0.232 Ω
Table 5-10.
USB Color Code
Insulation color
Green
White
Red
Black
Pin Signal Description
3 USB+ Data (plus)
4 GND Ground
Maximum Length
16.4 ft (5.00 m)
9.94 ft (3.03 m)
6.82 ft (2.08 m)
4.30 ft (1.31 m)
2.66 ft (0.81 m)
www.hp.com Technical Reference Guide