[Enhancement] Raw HDLC stream driver

[IW3IJQ]

During the golden age of Packet Radio the radio interface consisted of a modem connected to a Z80-SIO, as in TNC2, or the same type of modem connected to a Z8530 SCC, as in PA0HZP OptoPcScc or SuperVozelj multiport node.
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Some multiport nodes are still active with high-speed modems (38k4, 76k8, 1M2 bps). These modems carry a raw bitstream from/to the HDLC controller (Z80-SIO/Z8530). There are not many alternative controllers with modern hardware, and this can be a problem if the CPU board fails.

It might be interesting to interface the raw bitstream of these modems with the DireWolf HDLC controller using Raspberry GPIOs, or via USB with an RP2040 or an FT234.

[inschenioer]

I strongly second that request. This would enable "retro" devices like C64 and C128 to connect to PR via KISS, TCP, ..., too.

Those devices directly drive the TCM3105 at their interface port. So all needed would be to take the TTL-HDLC-Signal directly (before the TCM3105) and feed it to direwolf on GPIOs, ParPort or RS232 (with level converter). Direwolf then would directly process the TTL level HLDC stream without the need for modulation.

Once "inside" direwolf, the interface options would be wide open for this devices (KISS, KISS/TCP, ...).

IANAP, but seems to me only "stage" inbetween the whole process (modulation/demodulation) has to be omitted.