centronics interface schematics???

[janbredenbeek]

Hi,
The Raspberry PI can indeed be connected to other computers via the serial port connection accessed by the GPIO pins. I do not seem to find a use for this, as the Raspberry PI, while good product at a low price, is a slow Linux computer compared to the Core i5 computers I have running my Virtual network server.

The main problem with the GPIO interface is that it uses 3.3V signal levels rather than the RS232 +/- 12V (or even TTL 5V).
I have used the RPi for serial communication with a BBQL, but using a USB-to-serial adapter.

[Peter]

Yes a RS232 driver would be needed. Usually a matter of 5€ (or 2€ chinese). Also avaliable inside cables.

[Derek_Stewart]

Hi,

I used a MAX3232CPE, to connect to the RPI GPIO pins, see this link for details of the connection:
https://elinux.org/RPi_Serial_Connection

https://codeandlife.com/2012/07/01/rasp ... ax3232cpe/

Not quite straight forward, but works.

[bwinkel67]

I have a US Miracle Centronics Interface. It looks different:

Centronics.jpg

Oh, I have a USB one next to it that I bought a few years ago when I upgraded my desktop and still had an old parallel laser printer.

Hi,

The Miracle Serial to Parallel interface is not a specific US marketed interface.

This was the next version, in the Miracle Interface, I have one in use , but has a QL connector , rather than a DB9 connector.

The new interface was a major change in the way the converter was made.

I remember organising a QL Show in the North East of England, in the 1990s, where Stuart Honeyball wanting lots of publicity to promote this new product.

Hi Derek,

Did you ever complete the schematic for the Miracle System Centronics interface. I was trying to open mine up to take a peek but it's not as simple as I thought. It seemed like all you had to do is loosen the screws and pull it out from the front but that didn't work. I'd rather not break it but am interested in what chip/circuitry it uses. I saw one design based on the 74HC595 so curious what my smaller version uses (and how it does it).

[Derek_Stewart]

Hi,

There are 3 versions of the Miracle Serial-Parallel converter:

1) A cable at each end of the black box which holds the circuit board for the serial to Parallel conversion.
2) A Black box with a 36 pin Centronics male plug secured to the circuit board housing (Black Box)
3) What looks like a printer lead, with the Serial to Parallel conversion board enclosed in a Male 36 pin Centronics connector, and a lead going to the QL Serial port.

i will see if I can get these interfaces documented.