I did a thing called SyncDongle.( https://github.com/MattisLind/alfaskop_emu/tree/master/hardware/SyncDongle)
Essentially a BluePill with some level converters. It is using the SPI port for sync communication. Then I developed a BSC implementation and a HDLC implementation to use on the SyncDongle. https://github.com/MattisLind/alfaskop_emu/tree/master/Utils/BSCGateway/BSCBridge https://github.com/MattisLind/alfaskop_emu/tree/master/Utils/SDLCBridge BSCBridge is more finished and works quite well to communicate between a USB host (Hercules) and a BSC terminal controller. SDLCbridge is working but is unfinished but tested fine with some simple SDLC messages to a terminal so the low level stuff seemed to work. https://youtu.be/H1Sxt7xjn4Y https://youtu.be/CFfB3yCN9OI Not sure if 1 mbit/s is possible with the SyncDongle hardware. But it might be. /Mattis Den tis 26 jan. 2021 kl 02:46 skrev Paul Koning via cctalk < [email protected]>: > In playing with DECnet I built a DDCMP implementation which deals with a > byte stream, normally from a UART. So that works nicely with async link > DDCMP as found in RSX and several other operating systems. But the speed > is limited. > > The other option would be synchronous links, which would enable > connections to DMC11 or the like at speeds up to 1 Mb/s. But synchronous > comm devices that connect to modern computers aren't so easy to find, > though I have seen a few. > > After playing with Arduino for LK201 keyboard emulation I started to > wonder if one could be made to be a synchronous comm link with a USB back > end, with low level things like byte framing and maybe DDCMP packet format > handling in there, but the protocol state machine in the host behind the > USB interface. For moderate speeds that seems entirely practical. For 1 > Mb/s, probably not, though perhaps one of the fast ARM based units with its > built-in SPI could be warped into that. > > The alternative would be something like a BeagleBone Black (or Green) such > as David Gesswein used as the engine for his MFM hard disk emulator. That > clearly could do the job without any strain. > > So I'm wondering: would there be interest in such a thing? If yes, should > it be a modem-connected one (RS232 signaling, bit clock supplied externally > by a modem or modem-eliminator)? Or should it be the "integral modem" > short distance type, the ones that used a pair of coax with 4-pin AMP > connectors like this > https://www.digikey.com/en/products/detail/te-connectivity-amp-connectors/206060-1/15588 > ? > > paul > >
