Re: PhoneNet topologies

[johnt@meaddata.com (John Townsend)]

In article <1994Jan6.160525.9001@news.weeg.uiowa.edu>, snelson@umaxc.weeg.uiowa.edu (Steven Nelson) writes:
|> From article <2gcgil$8q1@meaddata.meaddata.com>, by johnt@meaddata.com (John Townsend):
|> > I have a question about how PhoneNet networks can be configured.  I want to
|> > use the existing telephone wiring in my house to connect my computers and
|> > printers in different rooms.  If I connect each computer to the telephone
|> > line and then chain printers off of one or more of the computers, that would
|> > effectively create several separate PhoneNet chains of one or more devices.
|> > Is that allowable?  Do I put a terminator at the end of every chain, or is
|> > there a limit to the number allowed on the network (such as the required
|> > two terminators on a SCSI chain)?  Will unused extensions in the house (i.e.
|> > telephone jacks without a computer connected to them) cause "bounced" signals
|> > on the line?  Thanks!
|> 
|> John,  you have a good project in mind.  My understanding of how a home
|> phoneline Appletalk network would work is this:
|> 
|> Most modern phone lines have four wires (Red,Green,Yellow,Black).  The red-
|> green form a pair and are the middle two on a modular RJ11 phone plug.  The
|> phone uses this as 'line1' - the standard phone line.  The yellow-black form
|> 'line2' and are usually unused - these will become your localtalk (appletalk)
|> lines.  Use farallon phonenet connectors or equivalents.  Connect each device
|> (computer or appletalk printer) to the phone line using the phonenet connectors
|> Use the dummy phone plugs with resistors (should be included with the phonenet
|> connectors) to fill any empty phone sockets (ie, terminators).  I've never
|> hooked a phone and a Appletalk device into a phonenet connector but I hope the
|> wiring is OK for phone use (it should be, phonenet uses the two outer wires so
|> I hope it preserves the integrity of the two inner 'phone' wires).

I believe you're correct; I'm just wondering where to put the terminators.
It seems to me that too many terminators (more than two?), which are nothing
more than resisitors across the two signal lines, would degrade the signal,
but the telephone wire has quite a few more jacks than that around the house.
The whole purpose of a terminator, as I understand it, is to prevent the
reflection of electrical signals at the physical end of a wire.

|> Printers attached to a computer are _not_ shared; they can only be used by
|> that computer.  To be shared (networked), a printer has to be Appletalk
|> connected (eg. LaserWriter II or appletalk imagewriter II) with its own phone-
|> net connector.

That's what I meant. :-)

|> If you get an appletalk network running, you might be tempted to pick up a
|> used system 7 mac for file sharing too.

Already did - an SE/30.  There's nothing like enslaving a Mac as a fileserver
for my II's.  Further gratification comes from knowing that the development
of this particular Mac was financed almost entirely by the Apple II line in
1988 or so.

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