So can we now safely say 2025 is the year of LocaTalk?
year of
linux localtalk on the desktop tbqh
As usual, really well executed and it looks lovely!
thankyou - you say this, but it may yet prove to be a polished turd. More testing is needed. The problem is that I am doing this the easy way, because I'm not good enough to do it the better way.
The way I'm doing this relies on the differential signalling of RS485: when a mac is transmitting a packet, it ought to assert a differential voltage across the transmission pair. The hub detects the differential voltage to detect a transmission, and when it sees one, passes that transmission through to the other ports.
This works well for hardware that follows the rules: but badly made or cheap "meh, it works with localtalk, ship it" hardware doesn't entiely obey these rules. In the "badly made" category, for example, the thing I made to have a localtalk activity LED on my appletalk router seems to result in 0.5V being permanently across the lines, which confuses the hub (and isn't standard compliant, I need to fix that). In the "cheap" category, I have my suspicions about the AsanteTalks - if I remember correctly (must do a teardown and document what's in one...) they don't actually have any kind of proper differential drive. A lot of these cheaper things rely on the fact that if you pass what they're producing through a LocalTalk or PhoneNet box, the results more or less look right enough to work, and that is probably the case for this hub too (it's also the case for, for example, AirTalk, where there are some things you have to have two localtalk boxes between it and them for various reasons).
The better way to do this would be with clock detection. This is actually what the Mac uses to do its collision avoidance - it checks whether there is any kind of clocked signal being received, and if so it won't transmit (the gory details of this are in
Inside Appletalk - I only just understand them so I may be misrepresenting this). But that's much harder and I don't know how to do it, so this will have to do for now.
So this is only a proof of concept. Now I need to work out if this is actually good enough for practical use or not.
. By far the most expensive component on here is the USB power connector, followed by the mini-DIN connectors, followed by the line drivers.
