Ref: 20320011
Title: Combining Thick Ethernet Cable and Thin Coaxial Cable Segments
Date: 5/3/91

Copyright 3Com Corporation, 1991.  All rights reserved.

3Com sells two adapters to combine thick Ethernet cable and thin
coaxial (RG58 C/U) cable segments.  Following are sample drawings with
explanations.

Note:  The formula for mixing thick and thin coaxial cable in a
segment is

         3.28 x A + B < or = 1000 meters with 3Com transceivers or
         2.70 x A + B < or = 500 meters with other transceivers

where A is the thin cable length expressed in meters, and B the
thick cable length expressed in meters.


1.  The Cable-to-Cable Adapter (3C540) has a BNC female on one end and
an N-series female on the other end.

One 3C540 adapter allows you to connect a thin cable to a thick cable:

                thin                   thick
          T-------------------[3C540]==========================T
          terminator                                  terminator


With two 3C540s, you can connect a thick Ethernet cable to two thin
coaxial cable segments:

               thin                 thick                thin
          T------------[3C540]================[3C540]--------------T
          terminator                                      terminator


2.  The Cable-to-Transceiver Adapter (3C541) has a BNC female on one end
and an N-series male on the other end.

With one 3C541 you can change the N-series tranceiver connector to BNC so
that thin cable can be used:

                    thin                          thick
           T------------------[3C541]|---|========================T
           terminator            ____|   |_____           terminator
                                 |  N-series  |
                             ----|transceiver |
                             |    -------------
                             |
                      AUI drop cable
                        to device


Using two 3C541 adapters, you can add a thick cable between two thin coaxial
segments, and also attach two DIX devices from two N-series transceivers:

             thin                   thick                     thin
        T-----------[3C541]|---|===============|---|[3C541]------------T
        terminator      ___|   |____       ____|   |____      terminator
                       |  N-series  |     |  N-series   |
                   ----| transceiver|     | transceiver |----
                   |    -------------      -------------    |
                   |                                        |
             AUI drop cable                         AUI drop cable
               to device                               to device


