Introducing (and interest check) AirTalk: Wireless plug-and-play LocalTalk dongles

[cheesestraws]

Yup. I don't know what it is - I think it must be the way that MacOS does power saving on the WiFi or something? Transfer rates from mini vmac over wifi are wildly inconsistent despite the application neither knowing nor caring that it's on wifi

 

[twelvetone12]

Do you guys think it would be possible to condense this on a modem adapter port for a l'ebook 100 series? My idea i just to drop the rs422 transceiver and connect the pic directly to the serial port. It would be basically like connecting AirTalk to a device with a serial cable, but never using rs422. I checked the powerbook 100 schematics and the both serial ports go to two ports on the serial controller ic, the only difference is that the external serial port has the 422 transceiver on it.
What do you think?

 

[cheesestraws]

Do you guys think it would be possible to condense this on a modem adapter port for a l'ebook 100 series? My idea i just to drop the rs422 transceiver and connect the pic directly to the serial port. It would be basically like connecting AirTalk to a device with a serial cable, but never using rs422. I checked the powerbook 100 schematics and the both serial ports go to two ports on the serial controller ic, the only difference is that the external serial port has the 422 transceiver on it.
What do you think?

So, you mean, take the single-ended output from the SCC and attach it straight to the single-ended input to the PIC? That feels like it ought to work, but obviously I haven't tried it myself. Would love to hear about it if you give it a try - have you found the schematics and so forth?

 

[twelvetone12]

Yup that is the idea! It is probably a huge overkill, but having a wireless powerbook seems fun! I have all the schematics and all the pieces, I'm just missing the PICs but hopefully they arrive soon.

 

[cheesestraws]

but having a wireless powerbook seems fun!

I think if you can get this to work, you will find other people want one too. It sounds like a lot of fun.

 

[tashtari]

I checked the powerbook 100 schematics and the both serial ports go to two ports on the serial controller ic, the only difference is that the external serial port has the 422 transceiver on it.

As I recall, only one of the two ports on the SCC supports LocalTalk, wouldn't that be the external one?

 

[cheesestraws]

As I recall, only one of the two ports on the SCC supports LocalTalk, wouldn't that be the external one?

I don't know about Powerbooks, but in the case of desktop Macs with a normal SCC, both ports support LocalTalk but the OS only makes one port appear. If you have either the drivers that come with the Internet Router installed you can use either, or I think there's a driver floating around somewhere that enables it for the modem port too.

 

[twelvetone12]

I studied the schematic a bit more: on the PB 100, the 85C80's SERIALA goes to the modem, all signals (except) are buffered via a 244, SERIALB just goes to the line transceiver (the schematic does not say what it is, I will open my unit later for curiosity) and then out to the port. So I think that unless there is a software limitation (scc's portb is hardcoded?) probably using a patched driver that shows the modem port could work.

Edit it is an LTC902CS, but I could not find a datasheet, in any case it does not make any difference since I would use the other port.

 

[cheesestraws]

using a patched driver that shows the modem port could work.

I'd suggest trying this one: this (attached; zipped diskcopy 4.2 image) is the official Apple driver that enables LocalTalk on the modem port as bundled with Apple Internet Router. Never used it on its own, but I don't see why it wouldn't work. It makes the modem port turn up in the Network control panel.

Probably worth trying it on a desktop Mac first .

 

[twelvetone12]

thanks! The extension loads and I can select the modem port, now I need to figure out a way to see if it actually works (I don't have another mac unfortunately), I guess if I hook up the scope to the TX pin I should see the initial LocalTalk messages when the computer powers up right?

 

[cheesestraws]

Yeah, see if you get something that looks like an attempted address negotiation on the Tx pin, I think.

 

[Andy]

Is the a program that can bridge LToUDP to EtherTalk? I have a couple of Macs setup with EtherTalk and that would let me connect a PowerBook over AirTalk and connect with them.

If not, maybe it wouldn't be too hard for me to write. Hmmmm.

 

[tashtari]

Is the a program that can bridge LToUDP to EtherTalk?

@sfiera 's MultiTalk can do it:

GitHub - sfiera/multitalk

Contribute to sfiera/multitalk development by creating an account on GitHub.

github.com

 

[Andy]

Ah thank you, that's perfect!

 

[DiskJockey]

So trying to get the right solution here (if there is one). RPi running netatalk 2.x- works. I'm gonna built tashtari's tashtalk when the parts arrive - yay. How do I get netatalk to use the tashtari? I see that tasktalkd uses the serial port for LT and creates a socket, but how does netatalk get configured to listen to the tashtari? So close...

And I don't need to use the ethernet interface at all. Just want service over the tashtalk.

 

[tashtari]

tashtalkd's function is to bridge between TashTalk's serial protocol and LToUDP - AirTalk does the same thing, bridging LocalTalk to LToUDP. Netatalk 2.x only speaks EtherTalk, so what you need is to bridge LocalTalk/LToUDP to EtherTalk. On a Mac, LocalTalk Bridge will do this; on an RPi, MultiTalk will do it. @sfiera is working on adding TashTalk support to MultiTalk so you can go from a TashTalk hat directly to EtherTalk but I don't know if it's complete yet.

how does netatalk get configured to listen to the tashtari?

I think you mean "TashTalk"... I'm "the Tashtari" and nobody listens to me. ;D

 

[RolandJuno]

Greetings! I purchased two AirTalks and they were super easy to setup and use. I've been using Mini VMac as well as a Classic II and both are working great with it. I love that printers such as my ImageWriter II w/ AppleTalk card "just work" with it. I was able to print a document from Mini VMac to the ImageWriter II which was a little mind blowing. Thanks for making such a fun and awesome piece of kit!

I even compiled Mini VMac with the LTO UDP option for PocketCHIP (the Linux handheld from a few years ago). I made a blog post about that if anyone is curious.

While printing, I did notice a lot more red LED flashes from the AirTalk than normal. It seemed to coincide with activity to/from the ImageWriter II. Looking closer, it's the "Err" red LED on the LocalTalk side. I'm wondering if my AppleTalk card in the ImageWriter II isn't working right. I tried both the AirTalk directly connected with a DIN 8 cable as well as PhoneNET adapters with the same red LED flashes on the LT side. Is this normal? What does the Err light indicate on the LT side?

Cheers!

 

[cheesestraws]

Thanks for making such a fun and awesome piece of kit!

Glad you're enjoying it!

I even compiled Mini VMac with the LTO UDP option for PocketCHIP (the Linux handheld from a few years ago). I made a blog post about that if anyone is curious.

That's really nifty. I enjoyed your blog post. Didn't know about the PocketCHIP before this, what a nice little thing.

Is this normal? What does the Err light indicate on the LT side?

The Err light on the LocalTalk side means either that a malformed packet has been received or that a lot of handshakes have been attempted in a row with no data being transferred. I don't have an AppleTalk ImageWriter to test this with myself, but other people with ImageWriters have reported the same thing as you, so I think it's normal. I suspect it's the latter case, where the ImageWriter is preparing to send data and then doesn't, or something similar.

If you're curious, every time the red LT LED lights up, it should emit a log message out of the UART. You should be able to spot the UART spot on the AirTalk board: the pins are labelled, and it should talk reasonably happily to any USB serialish adapter that can do 3.3V levels. The cases where the red LT LED lights can be found in the firmware with this search: https://github.com/search?q=repo:cheesestraws/airtalk LT_RED_LED&type=code

Hope this information is useful!

 

[RolandJuno]

If you're curious, every time the red LT LED lights up, it should emit a log message out of the UART. You should be able to spot the UART spot on the AirTalk board: the pins are labelled, and it should talk reasonably happily to any USB serialish adapter that can do 3.3V levels. The cases where the red LT LED lights can be found in the firmware with this search: https://github.com/search?q=repo:cheesestraws/airtalk LT_RED_LED&type=code

Very useful, thank you! I connected serial to the port at 115200 baud and powered on the ImageWriter II AppleTalk and after the print carriage settles, there's 10 seconds of solid LT error LED with many, many repeating errors in the console of "tashtalk: framing error of 0 bytes" interspersed with a few "tashtalk: /!\ CRC fail: 61834" (or 21114).

BTW, nice use of ANSI to color code the console output =)

Cheers!

 

[tashtari]

That's a lot of framing errors. In order for TashTalk to flag a framing error, it has to have detected a zero on the line that it detects as the attempted beginning of a flag byte (0b01111110), followed by more than six ones, which seems a little too precise of an error to have been triggered by line noise...

Anyway, I'd be interested to hear what the debug output is like when a print job is in progress. (Even more interested to see some scope traces of the line, but that may be asking too much...)