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Real instructions on getting a Lantronix UDS-10 serial-to-Ethernet bridge working

CommodoreTI-99/4A (edited to add data from IM for accuracy -- want this to be correct and complete)

The Lantronix UDS-10 is rather popular among the AtariAge TI-99/4A crowd. It's basically one port of a Cisco 2511; it's a bidirectional telnet-to-serial bridge. The TI folks use it to connect to the outside world, because it is extraordinarily unlikely that the TI will ever get even a ten-megabit PEB card, due to the screwed-up interrupt handling on the TI. It's also a fantastic alternative to the Commodore 64NIC+, without any of the compatibility problems that go along with it.

A fellow named "Omega" (or "Ohm"; real name elided here) put together a document that purports to describe configuration. I'll be right up front here and say that I don't care much for "Omega" (and he doesn't like me much, either). His antics were a large contributing factor to my departure from AtariAge. I see him as an "ideas man" ... not a guy that actually produces anything, but constantly chirps up with "wouldn't it be cool if somebody did X" and doesn't understand anything about engineering or technical design. I also suspect that he was the author of an anonymous nastygram to yours truly awhile back; I can't respect anyone who hides behind anonymity while engaging in armchair psychology.

His UDS-10 document, which I will not link to here, is a good example of that. It's about 80% correct, but like most things that Omega "creates", that 20% will kill you. Not a word in the document about what one would do with a UDS-10 fresh off of eBay, with completely incorrect network configuration. No, Omega would have the UDS-10 purchaser install a Windows program to search for the unit, then try to configure it via telnet.

As usual with things that Omega writes, that'll only work in specific limited cases (i.e., the eBay seller resets the UDS-10 to factory default before shipping) and doesn't mention the existence of newer/better firmware. But no worries, as the official documentation and firmware is still available from Lantronix. I've put up a mirror here, but here's the general gist of what you want to do:

  • Do not buy a UDS-10-IAP. It will not work properly due to fatal firmware bugs. You want a plain UDS-10. Thanks, IM, for the pointer -- I didn't know there was a difference between the two.
  • Plug the UDS-10 into a serial port (USB, onboard, whatever) connected to a real computer running a real terminal program. Settings are 9600 8N1. Hold down the "x" key ...
  • ... while attaching the UDS-10 to power. That'll force the UDS-10 into setup mode on the serial interface.
  • Hit 0, and set it up for an IP address of to make it do DHCP. Or set the proper IP address for your LAN. I assume that you know your own network better than Omega does.
  • Set whatever other parameters you want here. The important one is the IP address. Once back at the main menu, save and exit.
  • If you are doing DHCP, watch your DHCP server logs for the DHCP lease. If you're doing static IP, then wait about a minute for things to stabilize.
  • Grab "ltx5805.rom" from either the official Lantronix site or my mirror referenced above.
  • tftp to the UDS-10 IP address. Set binary mode. Execute "put ltx5805.rom 3L". The UDS-10 will upgrade to the latest firmware and reboot.
  • Hold down the "x" key in the serial terminal while rebooting to get back into setup mode.
  • Choose option 1.
  • Port speed maximum 2400 for TI (9600 for Commodore 64 over user port with UP9600 and so forth), I/F mode 4C, flow 02, port 0, connect mode D6, auto-increment. That's mostly the same as Omega's doc, except you want to use 0 for the source port (to randomize) and auto-increment (again, to randomize).
  • That should do it. Read the official docs for more information on how to use this device; don't rely on a random shiny PDF floating around AtariAge as an official source-of-truth.

    When you get your unit working on your TI, please patronize IM's resurrected HeatWave BBS at (port 9640). It's all well and good to telnet into your *NIX boxes to transfer files, but the real fun is the BBS experience.

    (Omega, I replied to your comment via the email address you broadcasted on AA. I'd like to continue that dialog with you, but lack of response tends to support my hypothesis as set forth in the first few paragraphs of my email. The ball is in your court)


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    Insane Multitasker on :

    It isn't quite up to snuff due to my time away, but if you are using an F18A system, I suggest grabbing a copy of TIMXT. It uses an approach to interrupts that hadn't been exploited before, enabling the TI to successfully receive and process incoming data at 38,400 without relying upon any hardware handshaking. I had to tweak my code recently as I discovered there were boundary conditions where the interrupt handler was called a few instructions too late, resulting in lost characters. The same RS232 handler could be used successfully with a 40-column standard 9918 system, I just haven't seen the need to do so as I prefer 80 column color ANSI. I hope to continue this project sometime in the future.

    Also, for those purchasing from e-bay there are a few versions of the UDS-10. The UDS-10-IAP, for example, is very similar to the UDS-10. Unfortunately, the firmwares are different, with the IAP having at least one bug that renders the device unable to communicate. I found this out the hard way when I took over running heatwavebbs, which may be reached at @ port 9640.

    Chris Kobayashi on :

    Hey IM,

    Wonderful to hear from you again. Yes, all of my systems are using F18As, although ${DAYJOB} has interfered with me doing any serious work on them ... just little one-offs like this, really.

    TIMXT looked like a winner when I tried the snapshot you sent me awhile back. I should go back through it and give you detailed feedback, if you're thinking of restarting it soon. Is the one you sent me still the latest version, or did you hack on it a bit more after that?

    Thanks very much for pointing out the issues with the -IAP. I've amended this entry to say (basically) "don't buy one". I've also put a plug for HeatWave in as well. I should log in again before I head back to China ...

    ... anyway, good to see you up and about.



    Ksarul on :

    It is nice to see your analysis of what needs to be done to make a UDS-10 work properly with the TI and build it into a step-by-step process that anyone can follow. This one joins my list of highly useful TI documents.

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