DEC VT05 with OS/8 -- basic system rebuild?

[Johnny Billquist]

ard at p850ug1.demon.co.uk (Tony Duell) wrote:

>> In general, when talking about DEC equipment, the answer to that 
>> question is *always* no, for the simple fact that DEC didn't do hardware 
>> flow control. Hardware flow control is actually against the RS-232 spec, 
>> and DEC didn't abuse standards (unlike most other companies).
> 
> This reminds me of a comment I made about the HP82164 (HPIL to RS232 
> interface). That thing follows the RS232 standard to the letter (for 
> example, it correctly handles the cotnrol lines in half duplex mode). 
> It's just a pity that nobody else does :-). Getting it to work with some 
> RS232 devices is 'interesting'..

Yeah. HP was actually the other company that actually seemed to read the 
standard. I don't know of anyone else than DEC and HP that even tried to 
actually follow the specs.
One could only wish companies had. Everything would have been soo much 
easier in that case. Now almost everyone is confused when it comes to 
serial communication, and it's not because it actually is difficult, but 
people have just become so confused because they think it works one way 
just because the equipment they have do it that way, and when coming to 
any other equipment, nothing works the same way they are used to.

>> (And to make it clear: hardware flow control is definitely not possible 
>> towards a PDP8)
> 
> 'Nothing is impossible except skiing through a revolving door' :-)
> 
> More seriously,. I would have thought you could make hardware 
> modifications ot the serial interface PCB, possibly to gate ome of the 
> ready signals with the flow control input. Or (in this case), detect the 
> CR (or is it LF that's the problem?) and then hold the ready line 
> deasseted either for enough time for the VT05 to complete its operation 
> or until it gets some ecternal acknowledge signal.
> 
> No, I am not suggesting this is a sensible solution to the problem,but it 
> is _possible_

You are right of course. If you modify the hardware, you can always 
solve the problem.
But it is probably a bit more complex than your suggestion above. But 
yes, any can be done.

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol