#
#  Cable information for the DY-4 DMV177
#
#  $Id$
#

Background
==========

All serial cables described in this file were built using RJ-45 ribbon
cables which were plugged into DB-25 or DB-9 adapters wired as described.
Matching the colors of the wires in the shell is the easiest way to 
make sure the cable is built properly.

The board is configured as follows:

  - An MC68681 is the first two serial ports.  These are RS-232 and may
    be accessed via the front panel or the P2.  The front panel connector
    has both A and B serial ports on a single connector. DY-4 part number
    "OBYC3ASSY901132-000 Rev-" brings these ports out to two DB-25 
    female connectors.

  - The MC68681 serial ports are also accessible on the P2 connector.
    DY-4 part number "OBYC3ASSY901080-004 Rev A" brings these out
    to DB-9 female connectors.  These were not used in this effort.

  - A Z85C30 is used for the third and fourth serial ports.  These are
    RS-422 and may only be accessed via the P2 connector.  These are
    brought out to DB-25 male connectors.  An RS-422 to RS-232 converter
    was used to interface with these serial ports.

References
==========

  - Linux Serial FAQ
  - http://ahmed.egypt.com/electronics/serial 
  - DY-4 Documentation

RS-422 Converter
================

An RS-422 to RS-232 converter from B&B Electronics was used to
adapt the RS-422 signals so they could be used with a normal
RS-232 serial port.  Here is the information required to purchase
one of these:

    RS-232/RS-422 Converter:     Model 422LCON
    Power Supply:                Model 422PS

    B&B Electronics Manufacturing Company
    707 Dayton Road
    PO Box 1040
    Ottawa, IL 61350
    Voice: (815) 433-5100
    FAX:   (815)434-7094


Front Panel RS-232 Connection to a PC
=====================================

    Board's DB-25    PC's DB-9     Color in
      Channel A         COM1        Shell
    =============   ============  =========
     RX on pin 2     TX on pin 2    Red
     TX on pin 3     RX on pin 3    Blue
    GND on pin 7    GND on pin 5    Black
    DTR on pin 20   DTR on pin 4    Brown

    No other signals are used.

RS-422 Connection to a PC
=========================

This requires two cables with the converter connecting them.

P2 RS-422 to the RS-422/RS-232 Converter
========================================

        Board's          Converter's    Color in
        DB-25           RS-422 DB-25     Shell
    ===============    ==============   ========
    TXD_A on pin 2     RDA on pin 5      Red
    TXD_B on pin 14    RDB on pin 17     Blue
    RX_A on pin 3      TDA on pin 2      Brown
    RX_B on pin 16     TDB on pin 14     Green
    GND on pin 7       GND on pin 7      Black 

  
     Converter's       PC's DB-9     Color in
     RS-232 DB-25         COM1        Shell
    ===============  ==============  ========
     TX on pin  2     TX on pin 2      Blue
     RX on pin  3     RX on pin 3      Red
    GND on pin  5    GND on pin 5      Black
    DTR on pin  4    DTR on pin 4      Brown

    No other signals