cctalk Digest, Vol 70, Issue 3

[Dave McGuire]

On Jun 3, 2009, at 12:03 PM, Ethan Dicks wrote:
>>> These devices had a lot of trouble with RS423, where the voltage  
>>> was much
>>> less than RS232. I don't recall the exact numbers but RS232 was  
>>> something
>>> about 12V swings
>>
>>  +/- 15V
>
> Formally, yes, that's the max signalling voltage, but in practice,
> there's a lot of 1488/1489 circuits powered by 7812s and 7912s out
> there.

   Very true; I was talking about the formal spec.  I *think* the  
spec actually says +3V to +15V and -3V to -15V, but I don't recall  
for sure and I don't have it in front of me.

>   I am pretty sure that the MAX232 can't get things better than
> about +/-10V (but I could be mistaken about that).

   The MAX232, if memory serves, is specced at 10V but usually tops  
out at 8-9V in my experience.  I sure do love those chips. :)

             -Dave

-- 
Dave McGuire
Port Charlotte, FL