IBM 3270 compatible terminal connected to Hercules IBM mainframe emulator.

Connor Krukosky connork at
Mon Aug 31 18:58:23 CDT 2020

Wow Mattis this looks great, fantastic work!

I will see if I can solder up a unit from what you have up on github on 
a perf board (I should have a few bluepills kicking around) and see if I 
can assist in some way with testing on a 3174-61R I have.
Unfortunately its the only one I have and I have a few 3270 terminals so 
I would like to keep it in my ownership.
But they definitely do show up, a lot more often than it seems the 
terminals do nowadays.

I have the Ethernet controllers for my 3174-R61 which I know people 
generally use for communications with things like Hercules but as those 
are much less common it would be nice to see if we can verify this works 
on these terminal controllers and make using 3270 terminals with 
Hercules more accessible to people!

If you'd like me to work with you on testing this let me know. I'll 
definitely see if I can try it out myself anyway.
Either way, fantastic work and thanks for putting everything up on github!

-Connor K

On 8/30/2020 02:23, Mattis Lind via cctalk wrote:
> I have been working on a project for some time to connect a IBM3270
> compatible Alfaskop terminal with its IBM 3274 compatible cluster
> controller to the Hercules mainframe emulator.
> Yesterday I eventually succeeded. I was able to login to TSO on my Hercules
> system that ran MVS 3.8j.
> Here are a couple quick video clips:
> To achieve this I created a small piece of hardware I called SyncDongle,
> essentially it's just a few level converters, connectors and a STM32F103
> blue pill.
> On the hardware I run a small piece of firmware, BSCBridge. It bridges
> between the sync serial BSC used by the Alfaskop cluster controller and the
> BSC variant that the 2703 emulation inside Hercules is using.
> More information here:
> and here
> There are good chances that the SyncDongle/BSCBridge combo could work with
> a 3274 or 3174 controller as well but I haven't tested since I don't have
> one. But no guarantees given, though. If someone has a spare 3174-51R,
> -61R, -81R or -91R I would be very interested in it.
> Actually there is a good chance that it could work with general BSC use.
> Maybe for NJE between Hercules and a real IBM machine? Or 2780/3780 RJE
> terminals? Or other third party 3270 terminals using BSC.
> The BSCBridge firmware only supports non transparent mode at this point, it
> works fine with Alfaskop since it does not support anything else. Maybe a
> showstopper for 3174 with 3279 terminals? SHouldn't be that difficult to
> add transparent mode if needed.
> /Mattis

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