From: Tony Duell <ard at p850ug1.demon.co.uk> To: cctalk at classiccmp.org Cc: jack.rubin at ameritech.net Sent: Mon, August 16, 2010 1:13:42 PM Subject: Re: looking for monitor and cable for DECmate II I've sent a copy to you off-list, but I see no reason why this shouldn't be discussed on the list too. The VR201 is a farily standard TV-rate (RS-170) composite video monitor. The only odd features relate to the DA15 connector -- it has no internal PSU (it gets 12V DC over this connector) and it includes the keyboard socket (simply connected to pins on the DA15) Therefore, it's not hard to make up a cable to use any standard composite video monitor. I'll include the notes I made on the 'universal Rainbow video cable' which is overkill for you (it includes the colour monitor sockets too, which won't work AFAIN without a colour video option PCB). If you just wire up the keeyboard socket (a 4-pin modular socket) to the DA15 and a suitable coaxial (RCA phone or BNC) to monochrome ouptu on the DA15, it should work fine. That is, wire the keybaord to pins 6, 8, 14, 15 and the monitor to 12 (signale) and 4 (ground) -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