The future of our hobby (was Re: ImageDisk project is canceled)

[Tony Duell]

> 
> Tony Duell wrote:
> 
> >[1] Note for the uninitiated. The IBM serial card has 2 odd features that 
> >were not present in most, if not all, clones. The first is that it can 
> >pull pin B8 (IIRS) low during I/O reads, needed if the card is used in 
> >slot 8 of the IBM PC/XT. The second is that it has a current loop 
> >interface  as well as RS232 .
> >
> >  
> >
> Does any of the newer serial cards have the current loop option?

I believe there have been current loop cards for PCs (the current loop 
interface was used industrially, and no I am not thinking of the 
_analogue_ current loop used for industrial sensors)). But I've not seen 
a combined RS232 and current loop card for a PC other than the original 
IBM one. 

> Was it only TTY's that used the current loop?

Oh no. A lot of serial terminals did (DECwriters, HP terminals, etc. IIRC 
the serial interface for the HP9825 series could do current loop (maybe 
the one for the 80 series to). Somewhere I have a couple of control 
interfaces that are current loop on the host side. I am alos pretty sure 
I've seem a modem with a current loop interface on it. And of course most 
minicomputers had current loop interfaces (if only to link to teletypes).

-tony