DEC rainbow 100 color cable

Rod Smallwood RodSmallwood at mail.ediconsulting.co.uk
Fri Aug 17 18:58:19 CDT 2007


Thanks Tony ... That's saved me a lot of searching. 
I managed to find a sync on green colour monitor. 
Its not DEC but 'twill do until a VR241 turns up.
A kind list member has found a real VR201 for me.

Rod
   

-----Original Message-----
From: cctech-bounces at classiccmp.org
[mailto:cctech-bounces at classiccmp.org] On Behalf Of Tony Duell
Sent: 17 August 2007 23:21
To: cctalk at classiccmp.org
Subject: Re: DEC rainbow 100 color cable

For reference, here is a file I porduced on the 'universal' Rainbow
video cable. It should indicate how to link up 2 monitors, etc. This is
not a DEC product, it's something I hacked together for my 'Bow.

-tony
--------------------------
A universal DEC Rainbow video cable
-----------------------------------

This cable allows almost all possible monitor combinations to be used
with the Rainbow (see below).

Connections : 
-------------

Rainbow end (DA15-S)

  1 >----------+---------+-- Blue Gnd
     9 >-------O---------O-- Blue
  2 >----------+---------+-- Green Gnd
    10 >-------O---------O-- Green
  3 >----------+---------+-- Red Gnd
    11 >-------O---------O-- Red
  4 >----------+---------+-- Mono Gnd
    12 >-------O---------O-- Mono
  5 >----+
    13 >-+     +------------ Power Gnd
  6 >----------+------------ Key Gnd
    14 >-------------------- From Key
  7 >----------------------- Power 12V
    15 >-------------------- To Key
  8 >----------------------- Key 12V



  Box-mounted connectors :

  VR201 (DA15-P)

  1 o
     9 o
  2 o
    10 o
  3 o
    11 o
  4 o-----------+--------+--- Mono Gnd
    12 o--------O--------O--- Mono
  5 o-------+---------------- Power Gnd
    13 o    |
  6 o-------+---------------- Key Gnd
    14 o--------------------- From Key
  7 o------------------------ Power 12V
    15 o--------------------- To Key
  8 o------------------------ Key 12V

  Monitor BNCs : 

   Red
  ( o )--------- Red Gnd
    |
    +----------- Red 

   Green
  ( o )--------- Green Gnd
    |
    +----------- Green

   Blue
  ( o )--------- Blue Gnd
    |
    +----------- Blue 

   Mono
  ( o )--------- Mono Gnd
    |
    +----------- Mono 


   LK201 keyboard (RJ11-- front face view)

                -------
                |     |
          -----        -----
          |                |
          |                |
          |                |
           --  ^  ^  ^  ^--
               |  |  |  |
 From Key -----+  |  |  +----- To Key
 Key 12V----------+  +-------- Key Gnd


Components :
------------

DA15S socket + hood (to fit Rainbow video connector)

DA15P plug + jackposts (for VR201 connection)

4 off 75 Ohm BNC sockets (for monitor connections). You could use other 
connectors, like RCA phono, but BNC are standard.

RJ11 socket, chassis mounting (for LK201 keyboard). Chassis mounting 
sockets of this type are very hard to find. I ended up making a bracket 
to clamp a PCB-mounting one to the panel

Metal box of a suitable size to hold the above connectors (apart from
the 
DA15S).

1m cable. At least 4 75 Ohm screened cores and 6 single wires. I used a 
'unversal SCART cable' which has 6 75 ohm screened cores (I simply 
ignored 2 of them), a 4 way screened cable (I used this for the 4 
keyboard connections) and 4 other wires (2 in parallel for each of Power

12V and Power Gnd).


Possible monitor combinations : 
-------------------------------
1) VR201 only
This is pretty useless, but you can connect a VR201 mono monitor using 
the DEC lead to the DA15P on the box. Connect the LK201 keyboard to 
either the VR201 or the RJ11 on the box.

2) Standard composite mono monitor
Connect monitor input to 'mono' BNC on the box. Connect LK201 to the
RJ11 
on the box. This works just like a VR201, but you can use any monitor

3) VR201 and separate mono graphics monitor
Connect VR201 to DA15P. Connect LK201to either RJ11 on the box or to
VR201. Connect second (composite) monitor to the 'green' BNC. You can
use
the dual monitor driver for GSX and have text on the VR201 and graphics
on
the second monitor

4) Two composite mono monitors
Connect one to 'mono' BNC, other to 'green' BNC. Connect LK201 to RJ11
on 
box. Using the dual monitor driver, you get text on the first monitor
and 
graphics on the second monitor

5) RGB (sync-on-green) colour monitor (e.g. VR241)
Connect monitor inputs to BNCs as follows : 
Red - Red
Green - Mono
Blue - Blue.
Connect LK201 to RJ11 on box. This gives the standard DEC color monitor 
connections giving green text and colour graphics using the colour 
monitor driver

6) RGB monitor and VR201
Connect VR201 to DA15P on box. Connect LK201 to RJ11 on box. Connect 
color monitor as follows
Red - Red
Green - Green
Blue - Blue
This gives separate text and colour graphics displays when used with the

dual monitor driver

7) RGB monitor and composite mono monitor
Connect mono monitor input to 'mono' BNC. Connect LK201 to RJ11. Connect

colour monitor as follows
Red - Red
Green - Green
Blue - Blue
This gives separate text and colour graphics displays when used with the

dual monitor driver








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