Re: Connecting to Ethernet

[Toby Reiter <str4552@OBERLIN.EDU>]

On Sat, 16 Nov 1996, David Empson wrote:

> Toby Reiter <str4552@OBERLIN.EDU> wrote:
> 
> > There was a recent discussion in comp.sys.apple2 about methods for 
> > connecting a IIgs to ethernet, and a lot of people proposed extremely
> > complicated and expensive solutions. One thing that I have seen here at
> > my college (Oberlin) has really piqued my curiousity. It is a cable which
> > connects to a serial mini din8 port, ends in what looks like a rs232 
> > serial connection (male I guess) which is then attached to a female rs232
> > which then become a ethernet, cable and is plugged into an ethernet port
> > on the wall. Does anyone know what this thing is, and could it be used
> > with a IIgs?
> 
> What is it connected to at the moment?  A Macintosh or something else?
I assume you mean my IIgs. It is connected to nothing (except all the 
ordinary cables of course). It also has a 14.4k modem.
 
> What sort of Ethernet port is it?  I assume it is a 10Base-T (UTP)
> connection, i.e. an RJ-45.
Don't quite know, but I assume so, it's the standard port used by the 
college for all computers connected to the network. 
> Is there any kind of box in the middle of the cable?  If not, I cannot
> see any way that this could possibly work as described.
Seriously, there is no box at all. The cable from the macintosh widens 
out into what looks like a standard male 25 pin connector, although there 
are only 6 actual pins. This is attached to a female black 25 pin 
connector. This then has a standard 10base-T (I assume) ethernet cable 
attached to it.  The speed of the connection is definitely NOT ethernet 
speed, probably about as good a connection as my IIgs on a modem at 
38400, but it would still be nice to have this connection if possible.

> Ethernet requires a 10Mbps serial connection with electrical
> characteristics that vary according to the cabling system.  The Mac
> serial port is not able to support this data rate, let alone meet the
> electrical requirements.
You're probably more of an expert here, but this is what I saw.
> The most likely explanation is that what you take to be an Ethernet port
> is actually a LocalTalk connection.  This would go to a bridge or router
> which converts it into Ethernet (this can be done in software on a Mac
> with LocalTalk and Ethernet support).
There are a few Mac Se's which I think are connected in this fashion in 
another part of the campus. But the one I am typing on right now is 
definitely using ethernet, as these ports used to be occupied by vt100 
dumb terminals (now occupied by Macintosh SE dumb terminals, what a waste).

> The Mac plugged into the cable would be using the AppleTalk protocol
> stack over the connection.  This would allow it to access devices that
> are using EtherTalk (AppleTalk running on Ethernet).  It could also be
> running TCP/IP, with the packets encapsulated using MacIP, which runs
> over AppleTalk.  This would allow access to devices on the Ethernet
> which are using TCP/IP.
Well, actually I'm not sure. These Mac SE's are using Kermit (relatively 
poor communications package) and are set up in such a way that the system 
is completely inaccessible. (All of the menu items besides Quit are 
disabled, so I can't even check the connection settings). I doubt 
seriously, that they are using TCP/IP since that package was only 
available (as far as I know) using System 7.x. They do have AppleTalk 
enabled, but I'm not sure whether that is actually necessary for the 
connection to be active (as I was able to shut it off and on again 
without losing my connection. 
> > Also, does anyone know if Macintosh servers can be accessed over an 
> > EtherTalk network? This would be nirvana for me, if this could be done.
> 
> I assume you mean from a IIgs.
> 
> Definitely, given an appropriate router between the IIgs LocalTalk
> segment and the main EtherTalk backbone.  The EtherTalk and LocalTalk
> segments may be set up different zones on the AppleTalk network, but
> that doesn't complicate things much.
> 
> If a simple bridge is used between the LocalTalk and EtherTalk segments,
> then they will appear to be part of the same zone, and it is even easier
> to access the server.
> 
> 
> Furthermore, if the IIgs was running GS/TCP and the bridge is a Mac
> running MacIP, then the IIgs would be able to access TCP/IP devices on
> the Ethernet by transmitting encapsulated IP packets over AppleTalk.
> (I'm not sure how this works in detail, as I've never seen a MacIP
> setup.)
I'm not much into purchasing anything more than about $20 to get this 
connection going. Routers run in the range of hundreds of dollars, right? 
I also don't have direct connection to a Macintosh hooked up to the 
network, (the closest Mac is a SE which would have to be connected the 
same way is this one is now). Anyway, I'm going to ask the people at the 
Computing center what exactly these contraptions are, just to see if it 
is feasible for my IIgs.

Thanks for all the input,
Toby