5.7.3 USB CONNECTOR
The USB interface provides two series-A connectors on the front panel and, on legacy-free
models, three series-A USB connectors on the rear panel.
Figure 5-10. Universal Serial Bus Connector
Table 5–19. USB Connector Pinout
Pin
Signal
1
Vcc
2
USB-
5.7.4 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).
Table 5–20. USB Cable Length Data
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.
Color code:
1
2
Table 5-19.
USB Connector Pinout
Description
+5 VDC
Data (minus)
Table 5-20.
USB Cable Length Data
Resistance
0.036
0.057
0.091
0.145
0.232
Signal
Insulation color
Data +
Green
Data -
White
Vcc
Red
Ground
Black
Third Edition - April 2001
Technical Reference Guide
3
4
Pin
Signal
3
USB+
4
GND
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)
Compaq Deskpro Personal Computers
Description
Data (plus)
Ground
5-25