Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!uunet!gandp!rg
From: rg@gandp (Dick Gill)
Newsgroups: comp.dcom.lans
Subject: Novice LAN Questions - Cheapernet
Message-ID: <313@gandp>
Date: 27 Sep 90 01:16:26 GMT
Reply-To: rg@gandp.UUCP (Dick Gill)
Organization: Gill & Piette, Inc.
Lines: 90


 
Hello

I hope I won't wear out my welcome with a few more questions.

I have decided to use standard thin ethernet (cheapernet) for
the lan based on the strong recommendation of net
correspondents, the confirmation by others that the unshielded
twisted pair technology is still new and delicate and, most of
all, the substantial additional cost in the interface cards and
the hub for twisted pair.

I am now into another new world (aka "learning experience" !-).  I
am familiar with the mechanics of coax from my years as a TV
broadcast technician but need a little help in the physical
aspects of building a cheapernet LAN.

1. Where (aside from friends on the net) should I look for
information about physically setting up a cheapernet lan?  Any
practical publications to recommend?

2. At the most basic level it appears that RG-58 (50 ohm) coax
is used with BNC connectors; are there any traps or potential
problems here?  What should I look out for in buying the pieces?

3. In terms of design, I understand that this is a bus topology
characterized by a single spine to which individual nodes are
attached.  I guess the simplest model is a coax connecting a
group of PC-NIC's via a "T" in the bus.

      T-----------//---------T--------//---------T------->>--<50ohm
      |                      |                   |
  ----I----              ----I----           ----I----
    PC A                   PC F                PC W
  ---------              ---------           ---------

Within the distance restrictions, is this model correct?

4. How long can a line to a node be from the bus?  Can, for example,
PC-D below be 30 feet from the bus?  How about 100 feet?

      T---------T-//---------T--------//---------T------->>--<50ohm
      |         |            |                   |
  ----I----     |        ----I----           ----I----
    PC A        |          PC F                PC W
  ---------     |        ---------           ---------
                |
                |
            ----I----
              PC D
            ---------

5. If the answer to 4 above is yes, can I further split that line
to create nodes PC-D(1) and PC-D(2)? 

      T---------T-//---------T--------//---------T------->>--<50ohm
      |         |            |                   |
  ----I----     |        ----I----           ----I----
    PC A        |          PC F                PC W
  ---------   /  \       ---------           ---------
            /      \
          /          \
      ----I----  ----I----
       PC D(1)    PC D(2)
      ---------  ---------

6. Because I will not be able to test the wiring before the job is 
completed, I would appreciate any other tips on how to do it right
the first time.

Please E-Mail; I will post or mail results as requested.
Thanks for your help.

Regards,

Dick Gill








-- 
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Dick Gill     Gill & Piette, Inc.      "I can be a humble guy when I need to." 
(703)761-1163   ..uunet!gandp!rg                                  Donald Trump