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Vintage Computers Any vintage computer systems, calculators, video games etc., but with an emphasis on 1980s and earlier equipment.

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Old 20th Jan 2014, 6:37 am   #1
mikeaosu
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Default Amstrad PCW 8000 series as dumb terminal?

Hi! I am just curious to know whether it is feasable or even possible to repurpose an old Amstrad PCW 8256/8512 as a dumb terminal? I mean the PCW CRT is a dec compatible terminal, so could I in theory pull the CRT from a PCW and hook up say a Single board computer to use as its VDU?

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Old 20th Jan 2014, 9:26 am   #2
paulsherwin
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Default Re: Amstrad PCW 8000 series as dumb terminal?

These are really just CPM computers and a number of emulators are available. I think the most popular one was called EMU, but I haven't had contact with this stuff for over a decade.
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Old 20th Jan 2014, 1:10 pm   #3
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Default Re: Amstrad PCW 8000 series as dumb terminal?

Yes, you would need software, and an add on serial interface.
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Old 20th Jan 2014, 2:00 pm   #4
mikeaosu
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Default Re: Amstrad PCW 8000 series as dumb terminal?

I suspected so, but thought it might have been done, can't see anyone on net having done this sort of thing though.
The Single board computer i had in mind was the N8VEM:
(a short description: http://n8vem-sbc.pbworks.com/w/page/...ign%20Overview )

N8VEM Project front-page:
http://n8vem-sbc.pbworks.com/w/page/4200908/FrontPage

They have built a board for vga displays, i am not sure if this would work somehow with the PCW display but i will ask on their forums.

Thanks Mike
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Old 20th Jan 2014, 3:15 pm   #5
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Default Re: Amstrad PCW 8000 series as dumb terminal?

I think you can reprogram the serial interface used for the printer to work as a comms port, but I've no personal experience of this.
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Old 20th Jan 2014, 3:36 pm   #6
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Default Re: Amstrad PCW 8000 series as dumb terminal?

The PCW display is bog standard 625 line 50Hz monochrome output. To communicate via a serial port the optional interface is needed which plugs onto the edge connector visible in the slot at the back.

The software is included on the CPM disc.

This interface is well and truly obsolete but I recall there was an article on building one in Practical Electronics back in the mid 80s. I'll dig it out and scan the article.

Keith
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Old 20th Jan 2014, 3:57 pm   #7
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Default Re: Amstrad PCW 8000 series as dumb terminal?

The basic-spec PCW doesn't have a standard RS232 port, although there is space in the addressing schema for one. Some PCW models were fitted with an RS232 and Centronics interface, for connecting to a "standard" printer (the Canon BJ10 was a very popular choice).

The add-on module is long obsolete but you might be able to get hold of the wiring diagram from somewhere and recreate it -- enough UARTs were made, over the years, that there is bound to be some old stock kicking about.

There should be a VT-52 or VT-100 emulator on one of the Amstrad system disks.
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Old 20th Jan 2014, 11:24 pm   #8
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Default Re: Amstrad PCW 8000 series as dumb terminal?

I think the interface is the CPS 8256; they have appeared on Ebay occasionally so possibly worth setting up a search to email you.
http://www.computinghistory.org.uk/c...=Amstrad%20PCW
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Old 21st Jan 2014, 12:51 am   #9
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Default Re: Amstrad PCW 8000 series as dumb terminal?

The PCW 8256 manual only devotes three pages in the CP/M section to Terminal characteristics, and most of this is a list of the control codes. It says that its terminal emulaor "provides facilities very similar to a Zenith Z19/Z29 monitor", and makes the PCW screen "broadly emulate a VT52 terminal".

The "Mini Office" suite of programs for the PCW, which was quite popular at the time, does include a communications suite, but as I never did get a CPS8256 interface, I had no occasion to try it. It offered custom configuration of the RS232 interface, plus pre-set options for MicroLink Gold 1200/1200; 1200/75; and 300/300; and Prestel/Viewdata 1200/75; 1200/1200; and 2400/2400. How things have moved on!
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Old 21st Jan 2014, 8:36 am   #10
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Default Re: Amstrad PCW 8000 series as dumb terminal?

I have the serial interface for the PCW 8256 and all system discs (along with a copy of minioffice) I'll have to get a cable sorted out, and see if I can get some files tranfered in either direction to/from a DOS based PC. I saw the comms programs on the minioffice disc, does that mean I could connect a modem and transfer files over the internet?

I have a spare display/CRT (well whole computer minus keyboard + printer) and so was just wondering if I could re-use the CRT, being an absolute novice I didn't know how easy/hard this would be, or if there were any major pitfalls.
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Old 21st Jan 2014, 10:51 am   #11
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Default Re: Amstrad PCW 8000 series as dumb terminal?

If you're searching for terminal emulation software, see if there is a version of "Kermit" available for your particular computer.

I've used Kermit on a whole range of different platforms [CP/M, MS-DOS, DR-DOS, OS/2, PDP10/11/20, ICL 1900/2900, and even IBM mainframes [which have some 'interesting' issues in symmetrically translating between their native EBCDIC character-set and ASCII] and it's probably the most flexible and configurable piece of terminal/file-transfer software you're likely to find.


See here: http://www.columbia.edu/kermit/kermit.html for the background.

There's an Amstrad Kermit - see here: http://www.columbia.edu/kermit/archive.html#cpm80

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Old 21st Jan 2014, 2:00 pm   #12
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Default Re: Amstrad PCW 8000 series as dumb terminal?

Thanks! Yes, I had Kermit in mind for the both the local and network file transfer (but wasn't at all sure about the network side).
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Old 22nd Jan 2014, 2:00 pm   #13
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Default Re: Amstrad PCW 8000 series as dumb terminal?

Thanks for all the helpful advice! It will be a nice little retro project using one of those old PCW CRTs. I kinda like the green glow and there are no shortage of replacements on eBay if anyone else wanted to try. With an N8VEM iI can run CP/M 3 and reuse my existing Amstrad software possibly, with a decent modern keyboard and printer and media storage plus lots more oomph!
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Old 22nd Jan 2014, 8:37 pm   #14
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Default Re: Amstrad PCW 8000 series as dumb terminal?

I've found the article on the CPS8256 interface copy. There are no constructional details but I'm sure if anyone wants to build one they can improvise a suitable PCB.

Keith
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Old 22nd Jan 2014, 9:08 pm   #15
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Default Re: Amstrad PCW 8000 series as dumb terminal?

That's a superb piece of reverse engineering! Figuring out what sort of chips were in the interface by watching which registers were accessed. Excellent stuff.
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Old 22nd Jan 2014, 9:35 pm   #16
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Default Re: Amstrad PCW 8000 series as dumb terminal?

I have to admit I know Brian Frost, who wrote the original article. We were at university together back in the 70s.

Keith
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Old 22nd Jan 2014, 10:58 pm   #17
mikeaosu
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Default Re: Amstrad PCW 8000 series as dumb terminal?

Thanks Keith, that was an amazing read - i'm glad you found it.

Btw I had no idea there was a modem program on the Amstrad system disc.
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Old 23rd Jan 2014, 4:10 pm   #18
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Default Re: Amstrad PCW 8000 series as dumb terminal?

If you need the service manual for the PCW I have a copy which I have scanned.

Keith
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Old 24th Jan 2014, 1:53 pm   #19
mikeaosu
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Default Re: Amstrad PCW 8000 series as dumb terminal?

Thanks Kieth! I have actually got a scanned copy myself

I think i have most everything i need.


Thanks Mike
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Old 24th Jan 2014, 4:06 pm   #20
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Default Re: Amstrad PCW 8000 series as dumb terminal?

That was a fantastic bit of "old-skool" hacking, to discover how the "official" upgrade worked and then recreate a perfect electronic equivalent!
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