Mart Oruaas wrote in a message to Bill Dennison:
 MO> no, there is an 50ohm resistor inside ethernet 10-base-2
 MO> terminator. some other network types use different
 MO> terminators, like those 75ohm ones for arcnet. 
ARCnet is nominally 100 ohms, with 93 ohms the closest standard value.
 MO> AUI itself can transmit signals over quite short lenghts.
 MO> there is always a trasceiver between the AUI drop cable and
 MO> the 10-base-5 "thicknet" coaxial cable. it's said, that AUI
 MO> is the "real" ethernet.
AUI is the original Ethernet, but I would not say it is more or less "real."
 MO> AUI is always present on the ethernet board, not depending on 
 MO> wheter there is an AUI connector or not.
This may have been true at one time with the old chipsets, but not now.
 MO> long-range signals(in RG58, UTP and "thicknet" cables) are got 
 MO> using transceivers between AUI and any specific cable. the only 
 MO> difference between "thicknet" and two other types of 10Mbit/s 
 MO> ethernet cabling is that "thicknet" needs an external 
 MO> transceiver. it's just too big to fit on the NIC. 
Most modern Ethernet cards use direct signal synthesis, not transceivers.
 
-- Mike
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