[H-GEN] Vintage computing mystery

[Russell Stuart]

On Fri, 2018-02-02 at 12:25 +1000, Jack Newport wrote:
> I found this old board/card in a box of miscellaneous scrap computer 
> parts. It has been assembled by hand as you can see in the photos.
> One of the chips is labelled with the date 15/6/92.
> 
> Pictures:  https://imgur.com/a/Aewpc

The pins connected to an external connectors are 1489's (which convert
between 5V and RS232's 12V).  The GI8247 is a dual baud rate generator
which is connected to the 8 ping header at the top.  I'm guessing
that's to allow the baud rate to be changed.  The MC6850 is a UART.

So the entire point of the thing seems to be driving RS232 signals
across the DB9 connector, with the baud rate selected by the jumpers.

I don't know what the 6809 CPU is doing.  It could be as complex as
driving some sort of protocol, or as simple as providing a FIFO buffer
between the serial port and the rest of the system.