Re: Connecting to Ethernet

[toh@freenet.Victoria.BC.CA (Marc Sira)]

In our last episode, Toby Reiter <str4552@OBERLIN.EDU> said:

>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.

It's common to wire serial connections over six or eight conductor "phone"
wire, and I strongly suspect this is what you're seeing. The pinout with
eight conductors looks like this; you can also use only the middle six
with software flow control, or the middle four with no flow control.

	RTS DTR TX+ TX- RX- RX+ DSR CTS

Since RS-232 uses a single conductor for TX-/RX- (ie. GND), the centre
two pins are usually wired together.

This could also be some kind of weird phonenet type arrangement, but
since you didn't mention a terminating resistor I doubt it. I think it's
just a serial line. If the Mac has a TCP/IP connection through there it
could be doing PPP on the direct connection (and could even do slow
Appletalk that way).

>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).

Ah, didn't see this 'til now (please try and put more whitespace in
logical places in your postings :). It's a serial connection, and the
Macs are simply using them as serial connections. 'Nuf said.

-- 
Marc Sira			   |
{ub675,toh}@freenet.victoria.bc.ca | "Your god drinks...p-p-peach nectar!"
{aa,xx}382@freenet.carleton.ca	   '