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Introducing (and interest check) CircuitTalk: LocalTalk for PowerMac G4

CircuitBored

Well-known member
Here's the iMac breakout board. This thing's come together way ahead of schedule!

DcKUsHO.png


The mounting holes for the structural pins of the mini-DIN connector will have to be castellated to allow the board to actually fit in place but I am pretty sure this is going to work great. I'll be ordering the first round of these boards very soon, along with the final version of CircuitTalk.
 

CircuitBored

Well-known member
The PCB order is in! I am right on track to have my first batch of final-version boards ready for sale by the end of the month.

Those who have expressed interest are already on the "reserved" list. Please let me know if you would like to call dibs on one of these boards.

Machines to be supported by the first release:

Sawtooth (AGP)
Quicksilver
Mirror Drive Doors
iMac G4 (USB 2.0)
 
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CircuitBored

Well-known member
It looks like my concerns about the early iMac G4s were unwarranted. That model shares the same modem breakout board as the later ones. This means that the iMac G4 version of CircuitTalk will be universal!
 

CircuitBored

Well-known member
I would love to get a Mac mini version to put in my mini G4.

@ArmorAlley has very kindly donated a Mini G4 to the cause so development of "CircuitTalk Mini" will begin soon! This version will also be the basis of the PowerBook G4 and eMac variants.

Did you know about Jamport from Alex Hixon ?
Jamport | Alex Hixon

That was my inspiration for this project! Sadly Mister Hixon has been absent for quite a long time, according to the forums he used to frequent. His version of gPort/StealthSerial is quite different from mine, being based on different transceivers and featuring almost no decoupling caps at all. From what I can glean he only produced around twenty Jamport cards before going off the grid. The PCBs he produced were also fairly low-quality, with nasty rough edges. That said, his work is impressive nonetheless and his research was invaluable to getting CircuitTalk off the ground.
 

zefrenchtoon

Active member
@ArmorAlley has very kindly donated a Mini G4 to the cause so development of "CircuitTalk Mini" will begin soon! This version will also be the basis of the PowerBook G4 and eMac variants.

Very nice to know ! :)
Many guys on MacOS9Lives! forum will be interested I think.

That was my inspiration for this project! Sadly Mister Hixon has been absent for quite a long time, according to the forums he used to frequent. His version of gPort/StealthSerial is quite different from mine, being based on different transceivers and featuring almost no decoupling caps at all. From what I can glean he only produced around twenty Jamport cards before going off the grid. The PCBs he produced were also fairly low-quality, with nasty rough edges. That said, his work is impressive nonetheless and his research was invaluable to getting CircuitTalk off the ground.
Ok, I hope he is ok …

If it can help, I've found a Griffin CubePort. I took it even if I do not have a Cube. I wanted to save it from bin ^^
 

CircuitBored

Well-known member
If it can help, I've found a Griffin CubePort.

Wow! That's an astonishingly good find! I'd love to see some pictures of it if you can find the time. I have been meaning to get my hands on a Cube for a while and this project is pretty much just the excuse I needed. I just need to set a chunk of money aside for one... The Cube is fairly low on the priority list for CircuitTalk variants (realistically it'll probably be one of the last ones I develop) but I definitely plan to get to it some day.
 

paws

Well-known member
The Powerbook Lombard (and I suspect Pismo) use the same modem board. I put a Stealth Serial port in mine. It doesn't fit physically, unfortunately, but I did get it to work with the keyboard detached.

Allegedly there's an extra USB port on the connector (see the pinout Alex Hixon published), as well as an audio input, I2C, and some GPIO. If there's space for it, you could add some solder pads to break some of that out. Maybe something cool will happen.
 

zefrenchtoon

Active member
Wow! That's an astonishingly good find! I'd love to see some pictures of it if you can find the time. I have been meaning to get my hands on a Cube for a while and this project is pretty much just the excuse I needed. I just need to set a chunk of money aside for one... The Cube is fairly low on the priority list for CircuitTalk variants (realistically it'll probably be one of the last ones I develop) but I definitely plan to get to it some day.
I will make detailled pictures ASAP (read: as soon as I received it)

I linked your work on MacOS9Lives! forums. :)

 

CircuitBored

Well-known member
The Powerbook Lombard (and I suspect Pismo) use the same modem board

Guess who got a Pismo (and a Wallstreet) recently! I plan to start work on a G3 PowerBook breakout board once my day job settles down after next weekend.

Allegedly there's an extra USB port on the connector (see the pinout Alex Hixon published), as well as an audio input, I2C, and some GPIO

There are indeed! I've been mulling over exactly what to do with this information. I doubt many people need an extra USB 1 port on their G4. An audio input could be useful given that the Quicksilver doesn't have one but its undoubtedly rather niche.

As far as I2C and GPIO go, there's definitely some fun to be had there. I think I could probably devise an alternative fan controller that actually responds to the CPU temperature in real time, as opposed to the bovine "thermistor on a fan" that the stock machines utilise. How about a fan controller with a little LCD showing you temps, CPU clock and fan speed? It could theoretically be programmed to do just about anything you want. I already have a breakout board assembled for the internal modem connector so once I have the time I will do some experimenting.

Got a fun idea for what to do with these connectors? Throw it in the mix!

I linked your work on MacOS9Lives! forums. :)

Thank you very much! I've been meaning to do that but have been somewhat bogged down by "real life" over the past few weeks.
 

paws

Well-known member
There are indeed! I've been mulling over exactly what to do with this information. I doubt many people need an extra USB 1 port on their G4. An audio input could be useful given that the Quicksilver doesn't have one but its undoubtedly rather niche.
One extra external USB port probably isn't so interesting, no. I use my Lombard for making music, and once I sketched out an audio-over-USB/MIDI-over-serial interface that would fit in the battery bay (with a flex cable to the modem connector on the mainboard), but to call that niche is probably an understatement. You could fit a Pi Zero in the desktops, though, and connect to the internal USB, but you're probably better off with it hanging off the Ethernet port.

As far as the audio input goes, I think it might actually be an extra, low quality ADC, but I don't know if that's actual information or something I made up. It's been a few years since I really thought about this.

Got a fun idea for what to do with these connectors? Throw it in the mix!

Fan control is one, as you say. Another one might be... something really cool. Direct hook up of i2c soil quality sensor or an 8k EEPROM? I don't know! But it's there, so we should have to have access to it. Right?
 

NJRoadfan

Well-known member
I have a G3 Lombard and a 15in Aluminum Powerbook G4 here. Color me surprised they share the same modem connectors as the desktop models! I would have thought the AlBooks would have switched to a USB modem vs. keeping a SCC on the board. The CircuitTalk board is going to have to shrink to fit some of these laptops though.
 

CircuitBored

Well-known member
Still in the market for a Quicksilver version.

I still have two early-access boards left! Shoot me a PM if you would like one but the snazzy purple boards are not far off now. I in fact just this minute got a message from DHL letting me know that they have arrived in the UK.

I have a G3 Lombard and a 15in Aluminum Powerbook G4 here. Color me surprised they share the same modem connectors as the desktop models!

To be clear: the G3 PowerBooks share their modem cards with the G3 and G4 desktops but the Aluminium PowerBook G4s use the modem cards also found in the Mac Mini G4 and the eMac (possibly the G5s too, I need to check my notes in the morning when my brain is in a less stupid mode). It really is bizarre seeing the desktop modem card in the G3 PowerBooks... it is also utterly infuriating that you must remove the CPU heatsink to get it out!

As for the Titanium G4s: their modem boards are still a bit of a mystery. I think that they are the same as the Aluminium/Mini/eMac boards but I've yet to find pictures that properly clarify that. In some images it almost seems as it they have a condensed version of the G4 desktop modem boards. If a brave Titanium owner is reading this, I need your help! A Ti is yet another Mac on my "to buy" list for CircuitTalking purposes.
 

CircuitBored

Well-known member
Fan control is one, as you say. Another one might be... something really cool. Direct hook up of i2c soil quality sensor or an 8k EEPROM? I don't know! But it's there, so we should have to have access to it. Right?

How about a simple breadboard that fits in the modem card slot so that developers can do whatever they want with it?

Another stupid idea: use the hidden USB port to create a "recovery"drive that has an OSX/OS9 installer on it.
 

paws

Well-known member
How about a simple breadboard that fits in the modem card slot so that developers can do whatever they want with it?
TBH even just having labelled solder pads would be fine, an (optional) 2.54mm header would also work.

Another stupid idea: use the hidden USB port to create a "recovery"drive that has an OSX/OS9 installer on i

I don't think that's a stupid idea at all. An internal port could also be used for USB wifi or bluetooth/wireless keyboard connectivity.
 

CircuitBored

Well-known member
An internal port could also be used for USB wifi or bluetooth/wireless keyboard connectivity.

@cheesestraws and I have discussed the possibility of combining CircuitTalk with AirTalk so that a G4 could be used as a router for wirelessly connected LocalTalkers. There's already a spare wireless antenna in the vicinity of the modem card from the now largely useless AirPort cards.
 
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