Networking a 6100

For direct connection you will need a crossover-cable. You may look here:
Apple products that require an Ethernet crossover cable
As hubs/switches are cheap you can use them with a straight cable. I use it to connect my two PM7600/XP-PC
Did not use AAUI-to Ethernet-transceivers yet, but should be same with filesharing/connecting.

My 6100 has a AAUI port on the logic board. I've networked it in the past with an AAUI-to-Ethernet transceiver. Connected to a simple enet hub leading to the cable modem, it could get on the Web but the screen redrawn was terrible slow.

Did test my four AAUI-to Ethernet-transceiver(PM 7600,OS9) with connection/filesharing.Works fine.Internet connection is possible(via switch,router,DSL) but really slow.
Can't test connection with OSX

A hub would be better. You can probably find a 10baseT for real cheap on eBay. My 8100 works just fine from the AAUI connector (using one of those transceivers). No Nubus card needed. While you're one eBay, do a search on eBay for "nubus." Some cool stuff shows up often, including Sonnet and NewerTech G3 accelerators.

I know my 6100 did come with an ethernet card and it was very easy to network. I used Farallon Eather Wave cables between my 6100 and my 8100.

I cannot answer your no. 2. it has been too long since I cracked open the case.

To answer your questions:

1. This model doesn't come with an ethernet card, but it already has built-in networking via the AAUI port. There is no need to purchase another separate ethernet card.

2. If you don't see a card plugged into the one and only PDS slot, then it doesn't have an expansion card installed.

If you want to network this computer, you must get an AAUI to 10BT dongle. Then you plug the ethernet cable into this dongle at one end, and the other end to the AAUI port on the computer. I suggest using either a hub or switch to create a home network. If you plan on expanding your home network in the future, a switch is the better choice.

MDD G4 Dual 1GHz, 1.25GB RAM, Radeon 9800 Pro, 2x80GB RAID Mac OS X (10.4.7) | TiPB G4 | B&W G3 | PPC 9600 | PPC 8600 | MDD dual G4 | Dell XPS3 |

You need to buy a AAUI to 10baseT transceiver and a crossover cable if you are not going via a hub i.e. machine to machine

You did the right research. The AAUI to 10baseT converter gives you the equivalent of an Ethernet card. You do not need anything else to give you network access.

A hub is more flexible if later, you want to add another device to your small network, such as another Mac or a printer. I don't see that a crossover connection is a "pain," but it is meant as more of a temporary connection, because you may also need to use that Ethernet port for your Internet connection.

What, if anything, is currently connected to the iMac's Ethernet port?

n8mac,

Just for the record, schools would frequently buy ethernet cards for those machines to get a 10/100BASE-T Ethernet connector (RJ-45) for faster data transfers on LANs.

The 6100 will do just fine for a data backup machine on a network so buying a 10/100BASE-T Ethernet card is recommended for speed - but not for cost efficiency.

The B&W was the first Mac that had Built-in 10/100BASE-T Ethernet. ( http://support.apple.com/specs/powermac/PowerMacintosh_G3Blue-and-White.html ). Not even the venerable 9600/350 had faster ethernet.

One word of caution, if you go with a hub and connect the iMac 400 to the web, you internet service provider will see all three computers and might bill you for three hookups. A router will prevent the entire LAN from being seen by the ISP.

Jim

A blue and white G3 would definitely be better, and there are more upgrade options for it (and it can run Mac OS X decently).

If you want to connect all your computers to the Internet at once, you need a device called a "router." The router connects to your broadband connection point, maintains the connection with the ISP, and allows the connection to be shared. Most routers also have 4 or more connection points and acts as a "hub" for the local network. An Ethernet hub (that's not a router) will easily connect all your computers together into a network, but will not connect directly to the broadband connection (although you can connect a hub to a router to increase the number of connection points or put a "node" in another room).

I'm not sure about the distinction between a "switch" and "hub."

"I'm not sure about the distinction between a "switch" and "hub."
"

Look here and follow the hyperlinks:
http://en.wikipedia.org/wiki/Router

Jim

A Hub takes the signals coming in on its cables and repeats them on all the other cables. It has no idea what it is repeating, including garbage if some device happens to spew garbage.

A switch takes in packets, checks them for veracity, and repeats the good ones. The most important concept is that a switch does a "store and forward" of complete, correct packets.

Some switches look at packet addresses and build internal routing tables and will forward packets to only the cable that has answered to that address previously. Some switches can change speeds to send packets from one device at 10 Mbits/s to another at 100 Mbits/sec.

A router, as the wikipedia article says, connects two networks. I used to run a two-port router -- one Internet port, one all-my-computers port. I has a separate switch. Most routers you buy today also include a 4 port or 8 port switch built in, which is very convenient, but makes understanding the various functions more difficult.