Upgrading my Apple II serial setup – colin@colino.net

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colin@colino.net

2026/06/14<br>About 6 minutes read

Last year, I upgraded my serial setup: before, I had to plug and unplug serial connectors from the back of the Apple //c each time I wanted to change the hardware plugged to it:

A Raspberry Pi, plugged to both ports, to browse Mastodon, listen to music with Wozamp, print to PDF, etc

A special cable, plugged to both ports, to use my Quicktake camera

A null-modem cable connected to my other Apple II to play a network game of Shufflepuck

A cable to print to a real ImageWriter.

I went with two serial switchboxes, and since then I didn’t have to unplug cables from behind my //c. It was much better!

The switch boxes are visible under each speaker

But it still had three drawbacks:

I had to press two buttons, one on each box, to connect to the Pi or to the Quicktake

So much cables

It was very time-consuming to solder all these cables, and replicating it would have been out of question

Why would I want to replicate it? Well, I know from my mailbox that a few people would have liked to try my projects, but the hardware part of it was kind of blocking.

All the serial hardware this required. The Raspberry Pi enclosure is not even in the picture!

Then I learnt Kicad as part of the BurgerDisk project, and very basic 3D modeling (with Tinkercad), and this unlocked whole new possibilities for me: First, I made an adapter PCB that makes it easy to connect a Quicktake to an Apple II, (and allows printing without unplugging the Quicktake). Then, I made a serial hat to make it easy to connect an Apple II to a Raspberry Pi (for my own projects, but it’d also work with ADTPro, A2Cloud, etc).

But, as much as those two are useful to people who want to use my Internet projects or my Quicktake for Apple II program, … it still requires unplugging cables from behind your Apple II.

So I have set out to make a large Raspberry hat that incorporates all of these. I found literal radio buttons (also known as, and easier to search for as, Piano Ganged Switches) and designed my PCB around them. I chose to have it fit in a 12cm x 20cm enclosure, the same form factor as Apple 3.5″ drives and the BurgerDisk. This PCB includes a MAX3232 chip and routes signals from the Apple II to the Pi GPIOs (and as such, is compatible only with Pi 4 and 5, as the 3 has less GPIO UARTs and it is on other pins).

The PCB’s top, with only the MAX3232 soldered

The back, where most of the routing happens

The radio buttons

The connectors at the back

One nice advantage of integrating everything is that I can have the Quicktake DTR hack always on, so I don’t need a button to select "Quicktake" on the Printer port. To meet my needs, I only need 3 toggles on the modem port: "Proxy main", "Quicktake", "Mystery" device (which in my case is my second Apple II); and 2 toggles on the printer port: "Proxy aux" and "ImageWriter". This translates to only 5 connectors at the back, which is good as they’re large and I wouldn’t have had more room anyway.

As the Apple IIgs doesn’t require the Quicktake-DTR-from-Printer-port hack, I added a jumper to route DTR to the Quicktake from either the Modem or Printer port.

I received the first batch earlier, and had time to assemble one to test it. I am both very happy and a bit disappointed: I forgot about DSR in the Quicktake use-case, and it doesn’t work out of the box. Moreover, the fix is different for the 8-bits (ACIA serial chip) Apple II computers and for the 16-bits (Zilog serial chip) Apple IIgs.

The Quicktake switch with the ACIA bodge wire: connecting DTR to DSR so that the ACIA is happy

For the IIgs, the fix is different, and simply consists of wiring the Quicktake’s DSR to the DSR pin on its switch.

So, I reworked the PCB, and replaced the jumper with a DPDT switch. The advantage is that it will be reachable from outside, so it can be used on 8-bits and 16-bits Apple II computers without requiring opening.

Another disappointment is the network cable to the Raspberry Pi: I don’t have enough room to add an RJ45 connector on the enclosure like I did for the power USB-C connector; so it has to go in and be routed through a dedicated hole, and due to this, the enclosure has to be opened to unplug the network cable. I think I will enable Wifi on the Pi to make things cleaner.

I would very much have liked Raspberry to limit themselves to two sides with I/O ports, preferably adjacent sides, but no, they had to put the MicroSD on one side, the power on another, and the RJ45 on a third one.

The network cable (white) going into the enclosure, from under the PCB

My last annoyance is the labelling. There’s just too much text to emboss/deboss it in the 3D print. I’ve made tests with transparent adhesive sheets from Amazon, and it’s disappointing: the ink is easily removed just by wiping the label with a finger.

I’ve made tests with Mod Podge, and it can look good, but it’s very easy to...