Super Serial Ethernet Card

3 posts / 0 new
Last post
macnoyd's picture
Last seen: 15 hours 15 min ago
Joined: Oct 15 2012 - 08:59
Posts: 844
Super Serial Ethernet Card

It's been a while since I began working on this card. Several years in fact. This project sat in a box awaiting construction after I got the idea that I wanted some sort of replacement to the Super Serial card that included an Ethernet interface. From the time I started working on this, the Uthernet Ethernet card had come and gone.
A sneek peek of this board's existence was entered back in 2015's Apple ][ vintage photo contest. (lower left corner of photo) Even then, it had been sitting around for a while. Still, I wanted one. Never bought the Uthernet version mainly because it had problems working on the original Apple ][ or Plus, and that was the target machine I was seeking to add this to. I'm unsure of the Uthernet status as of late.
I think those bugs were finally worked out, but I don't know for sure.

Obviously, adding Ethernet to a Super Serial Card would only allow limited use of the Card's serial options, but the idea of plugging your Apple ][, ][+ ][e or ][gs into your existing home's Ethernet and being able to transfer files over an Ethernet connection was and is an attractive option. So recently I set out to FINALLY finish the project.

The Ethernet interface I used is a Lantronix Micro125 Serial To Ethernet Server.
The nice part of using one of these is that you can wire it directly to the 6551 ACI chip without any buffering. Accepts the 5V logic both ways. Nice and easy, the way I like it. I literally tapped into the signals that go to the 1488 & 1489 transceiver IC's, so I can still use the Serial Port if I choose to do so.

Here is a detailed photo of my finished card: Super Serial Ethernet Card

You'll note I added a bit of nostalgia by using old hardware (white IC's) and an original Apple Prototype board. I replaced the crystal timebase with an Oscillator module, removed the Terminal/Printer jumper block, (it's wired in "Terminal" mode) and shifted things around a bit to make space for the Lantronix Ethernet Converter while keeping the original Serial interface connector. Plus, added a couple of LED's to indicate power and board activity status. It's a pretty packed board but not so much so that component placement would become a problem.

All hand built, point-to-point wiring. Just like the old days. Not especially pretty, but not too bad either. Took me an entire weekend to construct it and another weekend to troubleshoot my mistakes. (missing a few connections mostly) But I was able to plug it into Slot 2 of an Apple ][ Plus, dump a binary file I loaded from disk (FID) to my PC, (captured with HyperTerminal) and successfully reloaded it back to a freshly booted Apple ][ from my PC over Ethernet . Pretty neat.

Now the good, the bad, and the ugly... starting with the good...

This card will work in any slot, but fits nicely in Slot 2 where the connectors line up perfectly with the original Apple ]['s case slot. Once you power up the Apple ][, you can turn on the board with a simple "IN#(slot)" command. (slot being the slot number the card is in) From there, you have remote control of your Apple ][. By Typing "PR#(slot)", you are giving all screen output to the card as well. Exactly like the Super Serial Card does. Pretty easy. But the card will stay dormant until you manually activate it using the IN# command.
Configuring the Lantronix Ethernet card is also easy. Lantronix makes a nice utility to configure the Ethernet interface to the serial connection. I started with the max baud rate of the Super Serial Card (19.2K baud) and left it at that. Nice part is, beyond setting up the initial IP address or DHCP name, (I called mine Apple ][, go figure!) you can then connect externally from any computer and change settings via a Web page directly from your Web browser on your PC if you want. If you mess up the settings using the Web browser, (i.e. by making the connection unreachable) you can always go back to the Lantronix configuration utility to correct the settings. Nice part about all of this is that you don't have the hassle of having to write up your own configuration utility. It's all been done for you.
The Micro125 board is a Server of sorts and will also accept files via FTP -well beyond the file size of an Apple ][ disk, but I'm quite a way from tapping into this feature at this stage of the project.
There are no "enable/disable" switches that select Serial or Ethernet connections. They both run from the same source and can be used simultaneously. Not sure anyone would want to do that, but the option is there.

In a phrase, "19.2K Baud". SLOW. 1000's of times slower than the Ethernet card in use. I had to add character and line delays when sending a file from my PC to the Super Serial Ethernet card -even though I had handshaking wired from the ASIC. This is mainly due to the Super Serial Card's CTS signal (a bug) within the original 6551 IC. I know there's a fix to this if I replace the ASIC with a 65C51P2, but I've not done that yet and I still expect I'll need to keep a 40ms delay with every CR/LF because of the Apple ]['s interpretation speed. Whether using Serial or Ethernet, the effective throughput ends up the same... pretty slow.

The Ugly:
The other issue that concerns me is the amount of current the Super Serial Ethernet board uses. If I were to do it all over again, I would likely use an X-Port device. (a different Lantronix product). It's smaller and uses half the current that the Micro125 module uses. Total consumption of this board as it stands today is about 400 milliamps. That's a lot.

What's next:
I'm in the process of speeding up the baud rate of this board. I'd like to see if I can kick it up to 57.6K Baud. I know Reactive Micro was selling speed-up kits to the Super Serial Card several years ago. I'm guessing they were using the last revision 65C51P2 ASIC with a higher clock frequency but I never got to see how they were doing it. So, I've ordered additional timebases to see if I can bump up the baud rates to 38.4 and 57.6KBaud, maybe speed up character transfer a bit. Not sure how that will turn out but I'd like to make it run as fast as I can without unreliable transfer. I realize the Apple ][ bus in and of itself is a limiting factor.

Hope you all enjoy the fruits of my labor. I have no plan on making a PCB of this as of yet, but if anyone wants to take on that part of it, I'll work with you to help make it happen. I have a couple other projects in the works as of this writing. -Enjoy! MacNoyd

Dog Cow's picture
Last seen: 5 years 2 weeks ago
Joined: Dec 11 2008 - 16:26
Posts: 554
Re: Super Serial Ethernet Card

Never bought the Uthernet version mainly because it had problems working on the original Apple ][ or Plus, and that was the target machine I was seeking to add this to. I'm unsure of the Uthernet status as of late.
I think those bugs were finally worked out, but I don't know for sure.

The new Uthernet II works on the original II, II Plus, and standard IIe. Last I heard, there is going to be a redesigned version of Uthernet II, but I have no more information regarding when.

Here2Learn's picture
Last seen: 1 year 2 months ago
Joined: May 22 2013 - 20:37
Posts: 177
Re: Super Serial Ethernet Card

WOW! Congratulations to you sir! VERY NICE, even has a trophy plaque stand.

Log in or register to post comments