If a PCB is to encompass Ethernet, USB, and 1394 (FireWire), are 3
separate differential impedance pairs required? Here are the
requirements from the respective specs: Ethernet: 90 ohm +/- 15%; USB:
110 +/- 10%; 1394: 110 +/-10%. A PC motherboard designer should be able
to answer this.

Thanks in advance,

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