AVR-Chat

Peter Jakacki wrote:
> Russell Shaw wrote:
> 
>>It is no different now than then. Back then, RS232 was run around and
>>between buildings for terminals and mainframes. If you still want to
>>run those distances, you'll want +/-15V.
> 
> No, it is different and that is just the point. Nobody runs RS-232 
> between buildings, do you? If we don't go as far as using fibre then we 
> would use a balanced line drive like RS-422, but never ever RS-232. Yes, 
> I still want to run those distance, but no, I am not stuck in the 60's 
> because I use RS-422/485 or some other means.

I run rs232 from my workroom to the garage (30m).

At my previous job, rs232 was run from the lab to various measuring equipment
outside (10-20m).

I know of several radio hams that run rs232 from their radio room to things
outside and up radio towers (10-30m).

RS232 was designed for unterminated lines which keeps things simple,
especially for multi-drop star networks. RS485 requires a single backbone
with terminator.

RS232 can be fed thru radio coax and separated out with a filter, unlike
rs485 which requires a balanced line.

http://www.rs485.com/rs485spec.html

RS485 requires three wires but rs232 only needs two.