[comp.sys.dec] adding a modem to a decstation 3100

connie@psych.Stanford.EDU (Constance Stillinger) (03/14/90)

In article <8102@sdcc6.ucsd.edu> ux1925@sdcc12.ucsd.edu (burt bakor) writes:
> 
> 
> Help,
> 
> I'm trying to connect a hayes modem to a decstaion 3100 and can't
> seem to make contact with the hayes. Has anybody done this ? What 
> did your cable look like ( sigh, never had this problem with SUNS )?
> 

I'd like to second this request for info -- I'm supposed to get an
ethernet connection sometime in the indefinite future, but in the
meantime must make do with a modem for dialing in and out, if possible.

Thanks!


Connie
connie@psych.stanford.edu  (Now of Northwestern Univ., Evanston, IL)
-------

steve@wattres.UUCP (Steve Watt) (03/18/90)

In article <1063@psych.stanford.edu> connie@psych.UUCP (Constance Stillinger) writes:
>In article <8102@sdcc6.ucsd.edu> ux1925@sdcc12.ucsd.edu (burt bakor) writes:
>> 
>> 
>> Help,
>> 
>> I'm trying to connect a hayes modem to a decstaion 3100 and can't
>I'd like to second this request for info -- I'm supposed to get an

Funny you should mention that...  I was having this EXACT problem less than
two weeks ago...  I discovered that the serial port on the back of the
DECStation is (obviously! :) RS-423 (?!???)

What this means is that the voltage swing does not have to be as great as
RS-232 requires.

Solutions?  Two that I found:
1)  Buy a Telebit.  They don't seem to care
    much if the voltage is low....
2)  Some companies are rumored to sell RS232 boosters which supposedly do
    the trick.  I built one from 1488s and 1489s.  Drop me a line if you
    want a PostScript schematic.

-- 
Steve Watt
...!claris!wattres!steve		wattres!steve@claris.com also works
If you torture your data long enough, it'll eventually confess.