usr.sbin/isdn/isdntrace/cable.txt

   1  *---------------------------------------------------------------------------
   2  *
   3  *      Custom cable to trace an ISDN S0 bus with two passive (!) ISDN boards
   4  *      ---------------------------------------------------------------------
   5  *
   6  *      $Id: cable.txt,v 1.1.1.1 2001/01/06 13:00:29 martin Exp $
   7  *
   8  * $FreeBSD$
   9  *
  10  *      last edit-date: [Mon Dec 13 21:55:42 1999]
  11  *
  12  *      -hm     documentation of analyze mode
  13  *
  14  *---------------------------------------------------------------------------*/
  15
  16 The cable consists of a RJ-45 plug with both tx and rx connected and
  17 two jacks; the tx cables from the plug are wired to one jack and the
  18 rx cables from the plug are wired to the other jack.
  19
  20 The computer must be equipped with two (!) supported passive cards and
  21 the cable from one card is plugged into one of the jacks while the cable
  22 to from the other card is plugged into the other jack.
  23
  24 Now one card monitors the tx part of the S0 bus and the other card
  25 monitors the rx part.
  26
  27 Which card functions as the rx side and which as the tx side can be
  28 specified as options to the isdntrace utility (-R and -T) which has
  29 to be run in analyzer mode (-a) to support this configuration.
  30
  31
  32                                               1
  33                                               2
  34                                               3
  35                                +--------------4     receiving-side board
  36   S0-bus                    +--|--------------5     in computer (jack for
  37   to analyze                |  |              6     cable to passive controller)
  38                8            |  |              7
  39                7            |  |              8
  40     transmit - 6------------|--|--+
  41     receive  - 5------------+  |  |
  42     receive  + 4---------------+  |
  43     transmit + 3------------+     |
  44                2            |     |           1
  45                1            |     |           2
  46   plug into                 |     |           3
  47    S0 bus                   +-----|-----------4    transmitting-side board
  48                                   +-----------5    in computer (jack for
  49                                               6    cable to passive controller)
  50                                               7
  51                                               8
  52
  53
  54
  55            RJ-45 plug                        RJ-45 jack
  56         view from the front              view from the front
  57     cable goes out to the rear
  58
  59           /--------- /                      ----------
  60          | 87654321 |                      | 12345678 |
  61          |__      __|/                     |/_      /_|
  62             |____|/                           |/___|