Serial Adaptor

[Mk.558]

I'm looking to build a serial adaptor of sorts:

A small box that has a Mini-DIN8 cable for connecting to a Mac with a Mini-DIN-8 port. It also has a cable for a DE-9 port as used on the 512K and 512Ke.

The other side of the box, the output side, has a PhoneNET RJ-11 connector, and a RS232 DE-9 connector.

What does the crew think about this?

I took apart a TurboNET ST which I have, and it has some resistors (4), two LEDs, a SPDT (or could be SPST) switch, a shielded "box" of some sort. I took apart a PhoneNET box and it has some small black box, which I'm beginning to think is a isolation transformer.

I found this site but I don't read German, however it looks like it's chock full of tips. Anybody read Deutsch?

Depending on how difficult these are to build (they shouldn't be), it could be something I can cook up for a reasonable price. As far as I'm concerned, I'd need a DE-9 male to male cable (chop it in half = enough for two boxes), a RJ-11 jack, a Mini-DIN 8 cable, male to male (chop it in half yet again), a DE-9 female port (cheap), some prototyping board (varies), two red LEDs (Tx, Rx), some resistors, probably an isolation transformer and some cute box.

Thoughts?

 

[markyb86]

I like this idea. I have a Din8 male to rs232 de-9 female, plugged into a de-9 male to usb adapter.

So far no luck interfacing from system 7 to linux or osx 10.7.5.

I would like to be a guinea pig (by means of buying one of the first prototypes :b&w: )

 

[Mk.558]

I've thought about it for a little bit and realized that the open connectors are going to need terminators.

Otherwise, the signals will bounce off the "open" connection and echo back into itself, confusing the daylights out of it.

Soooooo the choice is either to use a DE-9 port for the input, with a mini-DIN-8 adaptor, or the reverse. Or I can provide both, but with a switch to select input from either the mini-DIN-8 or the DE-9 connector. Or I can provide terminators, either external (sound like a great thing to loose) or internal, selected by a switch.

Either way, it should be very much possible.

On my official (appears to be) PhoneNET adaptor, I fiddled with the ohmmeter to try to figure out the "black box". Assuming it's in the format of a transformer, I probed the "secondary" "side" and found a resistance of 1.4Ω. On the "primary" "side", the two outer pins have NC to each other, but #1 will have intermittent connection with #2 before it cuts out. #3 has an intermittent connection with #4, before it also cuts out. #2 to #3 has an ohm reading of 1.4Ω, suggesting to me that it is most likely a 1:1 transformer. But I don't understand the relationship between #1 and #2, #3 and #4 as stated.

On my TurboNET ST, I imagined (probably correctly, probably incorrect) likewise. This one had a reading of 1.0 for the "primary side" and 0.9Ω for the "secondary side". The "shield connections" to the board (they're soldered through and appears to be doubling as a jumper" has a ohm reading of 0.7Ω.

 

[Trash80toHP_Mini]

babelfish(?)

 

[RickNel]

the two outer pins have NC to each other, but #1 will have intermittent connection with #2 before it cuts out. #3 has an intermittent connection with #4, before it also cuts out. #2 to #3 has an ohm reading of 1.4Ω, suggesting to me that it is most likely a 1:1 transformer. But I don't understand the relationship between #1 and #2, #3 and #4 as stated.

That test behaviour looks like there is a capacitance between the two tested pins. There might be more than just a transformer - perhaps some filter caps as well?

Strongly recommend getting the web page translated - Google translate usually works well enough to get the gist.

Rick

 

[tecneeq]

Paste the part that google translate can't solve, i'll translate it.

 

[Mk.558]

The whole webpage would be great take your time if you need it, I'm in no rush -- just do like one or two paragraphs a day if that helps.

I picked up a nice condition Compaq E500. 14" XGA (1024x768), parallel port, IR, 2x PCMICIA, 1 USB (1.1), built in FDD, Composite Video out (although I'll be upgrading that to S-Video), and a DE9 serial port. Only problems are: 1) the serial port is missing pin 1, so I'll have to fix that; 2) a laughable 256MB of RAM *; and a paltry 10GB HDD.

It has Windows Server 2000 on it now, runs fine, battery lasts longer than I thought eBay could provide for a 25$ laptop (I had a E500 a couple years ago and liked it, until the power jack broke). Once I take care of these issues I'll set about figuring out the adaptor.

*: The Ethernet port is non operational, I assume because lack of driver support (shows up as such). Linux 10.04LTS wouldn't even load. 9.10 takes an unholy amount of time to even boot the live CD and took at least an hour to install. I don't have any compatible PC100 or similar memory at this time.

 

[tecneeq]

The whole webpage would be great

Sorry, i'm afraid you have to use google for the main stuff.

Did you see the references to the books at the end? That information would be first hand, and maybe the books are available in a (electronic) library.