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From: marki@tahoe.unr.edu (tahoe.unr.edu news administration)
Newsgroups: comp.sys.amiga.tech
Subject: Re: A Cost Effective MULTI-SERIAL Device Proposition
Summary: TTL-to-RS232 level converter
Keywords: RS232 MAXIM  MAX232 MAX233
Message-ID: <3560@tahoe.unr.edu>
Date: 11 Feb 90 02:35:02 GMT
References: <76649@tut.cis.ohio-state.edu> <90037.161429NETOPRBH@NCSUVM.BITNET>
Reply-To: marki@tahoe.unr.edu (Mark N. Iverson)
Distribution: usa, world
Organization: Desert Research Institute - Atmospheric Sciences Center
Lines: 35

In article <90037.161429NETOPRBH@NCSUVM.BITNET> NETOPRBH@ncsuvm.ncsu.edu (Brandon Hill) writes:
>
>First, the game port cannot alone drive a serial connection, as it is not
>set up to sink or source the currents required for a serial connection.
>
>Second, you can't directly receive RS-232 standard signals, because they
>can be anywhere between -12 and +12 volts (way out of line with what you
>can expect to apply directly to the game port)
>
>Therefore, you must have something to transmit and receive signals.  I have
>heard that the Maxim Max-232 can transmit and receive standard signals more
>or less from a 5 volt source using an internal DC-DC converter to drive the
>lines at near 12 volts.  If such a chip could service all the needed signals,
>it could probably be stashed inside the hood of a db25 connector...which would
>make the cable look like a simple db9 - db25 converter.
>
	[remainder deleted...]

I've used both the MAX232 and, currently, the MAX233 on my thesis.  The '233
has onboard capacitors and has worked with NO problems.  For testing, the 
thesis was inside of an environmental chamber and it was connected to a 
Sun-4; distance of 60 (sixty) feet.  I've done testing that took all day
(10 hrs) with the instrument (thesis) dumping at least several megabytes 
to the Sun with no problems... so far!!!

It generates ~+-10V from a single +5V supply.

...seems to be a good chip.  

--mark
-- 
Mark N. Iverson
uunet!unrvax!tahoe!marki            /  We dance round in a ring and suppose,
marki@tahoe.unr.edu  (scientists)->|   but The Secret sits in the middle,
marki@clouds.unr.edu                \  and knows.               -- R. Frost