Date   : Wed, 25 Mar 2009 09:24:47 +0000
From   : pete@... (Pete Turnbull)
Subject: Fwd: BBC B to PC serial cable

On 25/03/2009 08:20, Dethmer Kupers wrote:

> DB9 instead of DB25 should suffice, at least for in-home setups. At  
> 9600 baud, the 'official' cable-length is 150m;) At 19k2 you should  
> not exceed 15m. If you have a proper shielded cable, of course.

I think you're mixing up RS232 and RS423.  Max length often quoted for 
RS232 is 50 feet or 15m but the old standard actually said 45 feet as 
guaranteed distance and that the real limitation was on cable 
capacitance: you should expect to go much further with decent cable 
rather than lighting flex.  RS423 has limits more like RS422 (on which 
it is based), and the limit is more like 1000m at 9600 baud with proper 
120-ohm cable.  The limit at 19.2k is very much more than 15m, more like 
ten times that.  The BBC Micro family use RS423, not RS232.

-- 

Pete                                           Peter Turnbull
                                               Network Manager
                                               University of York