Re: Serial Communications

[Don Bruder <dakidd@sonic.net>]

In article <1130722451.883903.48870@g14g2000cwa.googlegroups.com>,
 "tolsen64" <tolsen64@hotmail.com> wrote:

> Does the GS just dump characters if the incoming text is too fast?  Or
> can that even happen?
> 
> Here's what I have:
> 
> GS -> Ethernet Modem -> Internet.
> 
> When I telnet out to a server (NNTP or SMTP), I lose half the
> characters in the response, so what i'm getting back is useless.
> 
> Both the GS and the Ethernet Modem's serial speed is set to 19200.
> 
> I thought it might be handshaking so I spent the day studying every "GS
> Handshaking" article I could fine (there are a lot of different
> versions of the beast).  All of them go from the MINI DIN-8 to DB-25.
> My Ethernet Modem has a DB-9 connector so I tried to "adapt" by
> cross-referencing the DB-25 signal names to the same on the DB-9.  But
> I couldn't get it to work (I couldn't transfer data at all) whichever
> cable i built.

When trying to build a comm cable, be certain you "cross" the Tx and Rx 
lines - IE, on one end, the wire is on the Tx pin, on the other end, the 
same wire is on the Rx pin, and vice-versa. Fail to do that, and what 
you're basically doing is trying to talk into the listener's mouth, and 
listening to the speaker's ear - with predicatbly poor results... 

> The cable I have working now works great as long as i'm not receiving
> more than a few characters at a shot.  The BBS currently runs using
> this cable.  I got this cable working by trial and error and I'd have
> to ohm it out to tell you what it's pin-to-pin connections actually
> are.  But it evidently doesn't handshake.

Yep, that sounds like your trouble... Unfortunately, I don't remember my 
II-hacking well enough to say which pins you need to put where to get a 
true hardware-handshake cable.

-- 
Don Bruder - dakidd@sonic.net - If your "From:" address isn't on my whitelist,
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