The NABU Network Adapter and NABU Floppy should been supplied with the NABU personal computer together with the CAM Module and Conditional Access Card.
@@retroCombs All of the parts required i.e the Network Adapter,Floppy drive,Keyboard and main processor unit should have come together as a complete package and you would also have got the CAM Module and card most likely a Nagravision Conditional Access Card.
When I first built my cable it seemed to work fine until CP/M came into play alot more. I would get errors all the time but the main network was fine. For me it was a ground issue with the cable once I redid it all the issues were gone. You don't show any grounding in the build.
I tried grounding and it didn't help. I'm leaning toward an issue with the Mac since I can now use a Raspberry Pi 400 with the Internet Adapter software without any issues.
The pin that is supposed to be GND on the DIN-5 pin isn't connected at all, not even in the schematic, and if you look into the DIN connector you see no metal at all for the pin to make contact with! so grounding is indeed useless.
If I'm not mistaken RS422 uses balanced pair transmission, and that means that the transmitter side of the connection needs to be terminated with an 180 Ohm resistor at the USB-RS422 adapter to work reliably. according to the NABU schematic the receiver side (pin 1 and 4 of the DIN) has that 180 Ohm resistor built in, but obviously not for the transmitter pair (pin 3 and 5 of the DIN) as the terminator must be connected to the end of the cable, so you must add the new 180 Ohm resistor to the screw terminals of the transmitter pair (receiver pair on the USB adapter side).
I bought a Delock RS422/R485 adapter, and yes, it does have a termination resistor on the receive side, 120 ohm according to the documentation. It also came with the screw block adapter.I suppose other RS422 USB adapter also have a built in termination resistor, as it is logical to include one.
