Interface 1 & Just speccy 128 rs232

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thesender
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Interface 1 & Just speccy 128 rs232

Post by thesender »

Hi

Im a little perplexed I have a 48k speccy with Interface 1 and 4 drives which i have connected to my laptop via rs232 and have no problems push stuff back and forth with the aid of SPXFR 0.99, I also have a JustSpeccy 128(lovely machine) with Interface 1 and 4 drives but no matter what i cant seem to send or receive anything no matter if im in 48 or 128k mode, does anyone know if this is an issue with the original 128k Spectrum as well and if so how to get round it ??
RWAP
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Re: Interface 1 & Just speccy 128 rs232

Post by RWAP »

Do you mean that you are using the same Interface 1 with both machines? You might also need to check which version of the ROM you have in the Interface 1 (I cannot recall what the change to this ROM was for).

I would be surprised if the original Speccy had this issue - it could be a timing issue with the Just Speccy 128 as I doubt anyone has tested it with the RS232 port on a ZX Interface 1 !
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1024MAK
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Re: Interface 1 & Just speccy 128 rs232

Post by 1024MAK »

Does the Just Speccy 128 have the +12V DC and the 12V AC (shown as -12V in some documentation) available on the edge connector? I think it is very unlikely. I think the Interface 1 "RS232" serial port needs both of these in order for it to work...

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thesender
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Re: Interface 1 & Just speccy 128 rs232

Post by thesender »

No I have 4 interface 1's,
2 version 2's which I am using on the 48k and the JustSpeccy128,
1 version 1 which is a bit flaky so I dont really use it and
1 thats unknown as it was dead when purchased.
The 2 Interface 1's i am using both talk to each other via the Sinclair network ok, and I have tried both of them on each machine individually, they both work with r232 on the 48k and neither work with the JS128 :( hey ho shame the JS128 doesn't have a built in rs232, So it looks like i will either just use winTZX with the JS128 or use the 48k as the link to the pc then use the Sinclair network to transfer stuff thus saving my tired Cartridges from 2 much more abuse.
thesender
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Re: Interface 1 & Just speccy 128 rs232

Post by thesender »

Hi 1024MAK im not sure someone else has also suggested that it maybe that the Lower 13 (~IORQULA) could be missing as well so i have sent a mail to Piotr to ask him if he knows why, perhaps in the end it'll just be the nut that holds the keyboard thats the problem ;) anywho when i get an answer i will post it.
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1024MAK
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Re: Interface 1 & Just speccy 128 rs232

Post by 1024MAK »

Have just checked the Interface 1 schematic and confirm that the "RS232" serial port section does need the +12V supply on edge-connector pin A22 AND the 12V AC supply on pin A23. The AC signal on pin A23 goes through a capacitor and is then converted to a -12V DC supply for the serial port circuitry.

Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp

:!: Standby alert :!:
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :!:
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thesender
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Re: Interface 1 & Just speccy 128 rs232

Post by thesender »

ok that looks like its the problem no voltage on those pins :( so no rs232 on the Interface 1 with the JS128, i dont suppose if there is a 12v somewhere it would be worth trying to add it to those pins ??
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