From: smace@nyx.cs.du.edu (Scott Mace) Subject: Re: Standard Speed/Length RS-232 Cable Limits Date: Wed, 14 Oct 1992 21:21:12 GMT
In article <1bhnv3INN7j6@uwm.edu> rick@ee.uwm.edu writes:
>michaelw@mcshh.Hanse.DE (Michael Will) writes:
>>I want to place my 386-machine running linux 0.98 in the cellar, since
>>it is rather loud (harddrives, fan) and I do not need graphics at the
>>moment.
>>
>>The cable for rs232 should not be longer than 12meters, right?
>>
>>Alas, I need it longer. I'd say it is about 20meters. [...]
>
>Here's the 'official' numbers (according to Cisco's router inst. guide):
>
>--- begin --- Quote of Cisco's "IGS Hardware and Installation Reference"
>
>Console Cable Considerations
> When setting up your system, consider electromagnetic interference
> and, when using RS-232 connections, distance limitations
>
>Distance Limitations
> As with all signaling systems, RS-232 can travel a limited
> distance at any given bit rate; generally, the slowere the
> data rate, the greater the distance. Table 2-1 shows the
> standard relationship between bit rate and distance.
>
> Table 2-1 RS-232 Speed Versus Distance
>
> Data Rate Distance (Feet) Distance (Meters)
> ---------------------------------------------------------
> 2400 200 60
> 4800 100 30
> 9600 50 15
> 19200 25 7.6
> 38400 12 3.7
>
At home I can run 38400 baud over a 100ft length with 0 errors. At
work, I can rarely get more than 20 ft. It all depends on the amount of
electromagnetic interference.