WORST keyboards ever

[J. David Bryan]

On 30 Aug 2004 at 7:20, Jay West wrote:

> Actually, it probably would have worked, as a common (although not
> required) setup for HP terminals was that the serial interface in the
> host was set for external baud rate, and the terminal provided the
> clocking. 

Indeed, it did work.  The 264x terminals had a rotary switch that set the 
baud rate clock supplied to the interface from 9600 down to 110.  It had a 
final position, "EXT," to set the baud rate from a clock received from the 
interface (though I don't recall ever seeing a terminal in use with this 
position set).  Some interfaces, such as the 12880A CRT interface, set 
their communication rate from the clock supplied by the terminal.

With such a setup, one could slow down a terminal listing by rotating the 
switch to a lower baud rate.  Because the switch was a break-before-make 
type, one could even "tease" the switch into an intermediate position 
(e.g., between 9600 and 4800 baud) to freeze the listing.

But I don't know why anyone would.  Two of the primary operating systems of 
the day, DOS and RTE, had terminal interruptibility (and, although I'm not 
certain, I seem to recall that TSB supported XON/XOFF).  Pressing any key 
while terminal output was in progress would pause the output between lines 
and issue a prompt for a system command.  So pausing a long listing was a 
matter of hitting SPACE to stop and RETURN to resume.

The only times I ever recall using the baud rate switch to slow down the 
output was when running the hardware diagnostics.  Even then, a few 
characters were typically lost during the switching, showing up as filled 
boxes (the DEL character graphic) on the screen.

                                      -- Dave