Connecting Macs

Originally published 01 February 2000 as a Mac Daniel column for Low End Mac.
Revised slightly 31 July 2003.

I'm often asked this question in various forms: "How can I connect my [insert name of one Mac here] and my [insert name of another Mac here]?"

There are essentially three options. The first two are the ones I least prefer (although there are certain situations in which you don't really have much choice).

Slow: Null Modem

You can connect two Macs with a null modem cable and transfer data through a terminal emulation program. I don't know much about this method, but I know that (1) it's slow and cumbersome and (2) it's not too useful unless all you want to do is transfer a few files.

Less Slow: LocalTalk

Your second, and probably easiest option, is some form of LocalTalk networking. If you only have two Macs to connect (assuming that neither is one of Apple's newer, serial port-less Macs), you can simply plug an ordinary printer cable into each Mac's printer (or modem) port and set AppleTalk to the appropriate port. Turn on file sharing on the faster machine (or the one with more RAM if they're otherwise equal) and then simply go to the Chooser of the other machine and select AppleShare. The Mac with sharing enabled will appear in the box on the right. Double-click it and type in the user name and password you set as the owner on that Mac. You now have full access to the remote hard disk(s) — and, optionally, other media.

A slight variation on this theme will work much better for connecting multiple Macs (up to about 30 or so, and if you have more than that, you're sicker than I am), since you can't have AppleTalk active on both serial ports at the same time (and thus can't daisy-chain Macs through the serial ports). Here's where the money (probably) starts to come in. Buy some PhoneNet connectors (although if you're really rich or have a good source, buy Apple's strange and proprietary LocalTalk connectors and a lot of LocalTalk cables and do the same thing) and some phone patch cables (or make your own cables if you're so inclined). Plug a PhoneNet connector into a serial port (they don't all have to be the same port, but it simplifies things somewhat if they are) on each Mac you want to connect. Use the telephone patch cables to daisy-chain the PhoneNet connectors. On each end of the network, use a terminating resistor in place of the telephone cable. Turn on File Sharing on the machines you want to use as servers and follow the procedures outlined above to transfer files. One of the advantages of this method (which also works with Ethernet, and is much faster that way) is that you can use it in a situation where the LocalTalk-based machines need Internet access (which, as far as I know, you can't do with a null modem cable and terminal emulation software, or at least not nearly as easily). Simply set up your fastest LocalTalk machine as an Internet router/gateway (this will require commercial software and an Internet connection for the router machine as well as TCP/IP reconfiguration on all the other machines) and properly configure the software and all the computers on your LocalTalk network will have Internet access. Another big advantage is all Macs have networking support built right in. You don't need any cards to use LocalTalk for your Macs (although printers are generally a different story).

Fast: Ethernet

LocalTalk's biggest disadvantage is speed, which brings me to the third and final option: Ethernet. There are, for all practical purposes, essentially two types of Ethernet: 10Base-2 (or thin net) and xBase-T, where x is generally (in home networks) 10 or 100. (Gigabit, or 1000Base-TZ, Ethernet exists, but I'm not going to cover it here since Gigabit Ethernet isn't available in NuBus form.) The 10, in both types of Ethernet, stands for 10 Mbps, or 10 megabits per second, the speed of the network. (By contrast, LocalTalk runs at a measly 240 kbps, or 0.240 Mbps.) The major differences between 10Base-2 and 10Base-T are the cabling and network layout. 10Base-2 uses thin coaxial cables (thus the name "thin net") and is a daisy-chain, terminated architecture. 10Base-T, by contrast, uses phone-like cables, called Category 5 (10Base-T also uses Cat 5) and is a star architecture, which requires the use of hubs.

If you already have some older Macs with Ethernet, the likelihood that you have some 10Base-2 devices is pretty high. Many older Ethernet cards had two connectors: an AUI (DB-15F, which looks like a monitor port — but don't plug a monitor into it) connector and a 10Base-2 connector. You can set up a 10Base-2 network relatively easily — you just have to buy cables and T-connectors (and terminators, if you don't have them). Simply plug a T-connector into the 10Base-2 port on the card and connect a cable from that to the next Mac's T-connector. Terminate both ends of the network. (This is really very similar to the LocalTalk method described above.)

If you don't currently have any Ethernet-based devices and you'd like to put together an Ethernet network, I'd recommend, simply because of ease of use, that you put together a 10Base-T network. While it might be slightly more expensive, it's very easy to find 10Base-T accessories now, while finding 10Base-2 accessories, is, in my experience, much more difficult. And if you have several Macs with 10Base-2 connectors but no 10Base-T, and you still want to use 10Base-T, don't despair - you can usually find AUI transceivers to attach to the AUI port on that Ethernet card that will give you a 10Base-T port. To set up a 10Base-T network, just get a hub (8 ports is the minimum I would recommend for future expansion purposes, and if you have a lot of Macs, investigate getting a 16-port hub) and some Cat 5 ethernet cables. (If you own Macs without built-in ethernet, you may need to purchase an ethernet card for each Mac you want to connect as well.) Run a cable from the hub to each Mac you want to connect. Plug in the hub's power supply and connect it to the hub. Make sure you switch the AppleTalk connections on each Mac to ethernet (and if you have to get cards, make sure you install the drivers first). Once you do that, you should be up and running.

One last point, somewhat related to both ethernet and LocalTalk: if you have a computer with both types of interfaces (any Mac with an Ethernet port/card will work as long as it has a standard mini DIN-8 serial port too), you can set up that computer as a LocalTalk Bridge. Connect both networks to the machine (ethernet to the ethernet port, LocalTalk to a serial port) and go to Apple's SW Updates site. Apple has released their LocalTalk Bridge software for free (it's unsupported, however) and you can download it there. Simply install the control panel and restart. Now all your LocalTalk devices will be able to access the Ethernet portion of your network.

Why, you ask?

Simple — there are those of us who have one or two printers, several Ethernet-equipped Macs, and several Macs with don't support Ethernet (namely the Classic, Classic II, Plus, and earlier models — unless you want to use a SCSI-to-Ethernet adapter, which still won't work with the 128 or 512) but do support LocalTalk. With a LocalTalk Bridge in place (I use an SE/30 for mine, and have a LaserJet 6MP, LaserWriter, Classic, Classic II, Plus, and SE on the LocalTalk portion of my network), all the LocalTalk devices can see (and, optionally, be seen by) all the ethernet-equipped devices.

If you have other Mac networking questions, Three Macs and a Printer is the definitive Mac networking site on the web today. If I didn't answer something here, or it isn't clear, check out Three Macs.

copyright ©2000-2004 by Chris Lawson