Front Panel I/O Connectivity Design Guide

Cabling Design Guidelines

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NOTE

Computer systems that have an unshielded cable attached to a USB port may not meet FCC

Class B requirements, even if no device or a low-speed USB device is attached to the cable. Use

shielded cable that meets the requirements for full-speed devices.

Table 20. USB Cable Recommendations

Characteristic Specification

Flammability Rating UL-94 VW-1

Insulation Resistance 5 k @ 300 VDC

Temperature Range - 55 °C to + 80 °C

Withstand Voltage 1000 VDC @ 60 Hz

Plating Per materials list

Wire Per materials list

Workmanship Parts shall be uniform in workmanship and appearance. There shall be

no excessive nicks, deep scratches, excessive burrs, or defects in

materials that may affect the function, serviceability, or appearance of this

part.

Contact Retention Force Equal to or greater than 2.0 ounces per contact, when unmated from the

proper connector

Maximum Insertion Force 10 pounds per connector

Dimensioning and Tolerances Per ANSI Y14.5M unless otherwise noted on drawing

UL Marking The cable manufacturer should supply UL Recognized cables that are

certified under the UL wiring harness program (ZPFW2). The UL

recognition mark should be supplied with the smallest container or bundle

of cables with each shipment.

The UL recognized wire’s insulation will have surface printing identifying

the style, flammability rating, manufacturer’s name, operating voltage and

temperature ratings, along with the UL recognition mark.

4.5 IEEE1394 Cabling (Motherboard to I/O Interface Board)

4.5.1 Introduction

This chapter provides some details of the design for a front panel IEEE 1394 interface cable to be

used in conjunction with the front panel I/O interface board and main board. The interface cable

must be shielded as specified in Figure 20 for two reasons:

• To ensure the cable data lines meet the required differential characteristic impedance as given

in the IEEE 1394 specification. Cables with an impedance variation outside of the IEEE 1394

specification limits will degrade signal quality and could cause front panel IEEE 1394 devices

to fail to operate reliably.

• To shield the cable from RF emissions inside the chassis. Improperly shielded interface cables

can pick up these internally radiated signals and cause the system to fail EMI testing.

Figure 22 shows the recommended IEEE 1394A/B interface cable details and pin assignments. Pin

assignments are further detailed in Table 21 and Table 22. The cable materials (including