HP (Hewlett-Packard) KP721AV Personal Computer User Manual


 
5-12 www.hp.com Technical Reference Guide
Input/Output Interfaces
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).
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.
Table 5-8.
USB Connector Pinout
Pin Signal Description Pin Signal Description
1 Vcc +5 VDC 3 USB+ Data (plus)
2USB- Data (minus) 4GNDGround
Table 5-9.
USB Cable Length Data
Conductor Size Resistance Maximum Length
20 AWG 0.036 16.4 ft (5.00 m)
22 AWG 0.057 9.94 ft (3.03 m)
24 AWG 0.091 6.82 ft (2.08 m)
26 AWG 0.145 4.30 ft (1.31 m)
28 AWG 0.232 2.66 ft (0.81 m)
Table 5-10.
USB Color Code
Signal Insulation color
Data + Green
Data - White
Vcc Red
Ground Black