The Sinclair QL Forum

Hallo,
I’ve recently got a centronics printer interface, but unfortunately its original plug has been cut and lost. Probably it had been modified for other computers (ZX spectrum, I guess?).
In any case, I have to restore its wiring in order to match the Sinclair 6 pins SER1 port.
The interface is the white one; please see the pictures linked here below.
There are 4 cables: yellow, red, blue and black. Could someone help me to reveal the 4 signals in order to find the correct wiring for the non-standard (UK style) SER1 port please?
Thanks

https://dl.dropboxusercontent.com/u/397 ... tr_int.jpg
https://dl.dropboxusercontent.com/u/397 ... r_back.jpg

I can help with this (as I have one of these interfaces), but not until Friday or Saturday due to a lack of time (life and work ).

Mark

1024MAK wrote:I can help with this (as I have one of these interfaces), but not until Friday or Saturday due to a lack of time (life and work ).

Mark

Thank you so much for your help Mark. Don't worry, I can wait

Okay, here is a picture showing how the plug is wired on mine My interface is slightly different to yours, mine has a diode on the back instead of an extra transistor The plugs used are no longer made. They sometimes available second hand, but not very often.
However, with some handiwork, a 6 way BT type telephone plug can be used.
You can modify either the QL socket with a sharp knife and a needle file, a standard 6 way BT type telephone plug can then be used. Or instead, you can cut grooves in a 6 way BT type telephone plug then the QL socket does not need to be modified.

If you need more pictures, shout out

Anyway, I hope this helps

Mark

1024MAK wrote: My interface is slightly different to yours, mine has a diode on the back instead of an extra transistor

Do you think this could be a sort of homemede modification (for some unknown purpose), or a possible "standard" modification by Miracle Systems?

1024MAK wrote:You can modify either the QL socket [...]

Don't touch my QL SER socket! Fortunately I do have an original plug
So the red wire seems connected to the 12V pin, black->grnd, yellow->RxD, blue->DTR(=RTS).
Your pictures are almost professional and crystal-clear; many thanks also for your valuable help
I'll make some proofs and let you know

Hi,

I have seen some German QLs with 9 pin D Sockets in place of the SER1/2 & CTRL 1/2sockets, I must admit to liking this as a better standard than the original sockets and would also integrate into a better look for a added QIMI socket on the rear of the QL.

Maybe something to do with the working QLs I have.

Derek_Stewart wrote:a better standard than the original sockets

Surely it's a better standard but, as you know, usually the words "Sinclair" and "standard" don't match very well..
Regards

Cristian wrote:

1024MAK wrote: My interface is slightly different to yours, mine has a diode on the back instead of an extra transistor

Do you think this could be a sort of homemede modification (for some unknown purpose), or a possible "standard" modification by Miracle Systems?

I don't know, I don't think it's homemade. On mine, they have removed the markings of the two chips.
So I suspect that yours is either an earlier version before they thought of this "lets remove the markings so it's harder to copy" idea, OR by that time they had given up removing the markings!

It may be that the transistor on yours and the diode on mine are effectively doing the same job. Without working out how the circuit works, we can only guess

Mark

1024MAK wrote:"lets remove the markings so it's harder to copy"

In any case, I've just connected the wires and...Bingo!!!!! It prints from Superbasic and from Easel
For the moment there's still something I don't understand: the printer (Brother HL-5040) receives data, but it stays paused until I push the botton "go", and Quill doesn't print ("can't open the file"). I have to do more tests.
Thank you so much Mark!

Cristian wrote: For the moment there's still something I don't understand: the printer (Brother HL-5040) receives data, but it stays paused until I push the botton "go", and Quill doesn't print ("can't open the file").

Apparently, your printer doesn't start to print until it sees a form feed. Most lasers work like that. Make sure your output to the printer does contain that at the end of each page.

Tobias