Re: Using MC1488 for TTL->RS-232

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Article #21987

#21987

From: aaron.michael.chesir
Date: Thu, 04 Jan 1990 13:46

41 lines
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In article <MZb4w2600WB88M=4wv@andrew.cmu.edu>, kg19+@andrew.cmu.edu (Kurt A. Geisel) writes:
> Help a poor non-EE :
> 
>                   2 |----------| 3
>      TTL ---------->|          |---------> RS-232
>                   1 | MC 1488  | 14
>      -5 V --------->|          |<--------- +5 V
>                   7 |          |
>      GND ---------->|----------|
> 
> What I get:
> 
> When the TTL input is at 0 V, the RS-232 output is at 3.25 V.  When
> the TTL input is at +5 V, the RS-232 output is at 3.94 V.  Needless to
> say, this is useless.
> 

Your problem is that the MC1488 takes +- 12 (TWELVE) Volts, not +-5V.


Aaron Chesir
..att!twitch!aaron
.

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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!att!cbnewsh!aaron
From: aaron@cbnewsh.ATT.COM (aaron.michael.chesir)
Newsgroups: sci.electronics
Subject: Re: Using MC1488 for TTL->RS-232
Summary: Wrong Power Supply!
Message-ID: <7041@cbnewsh.ATT.COM>
Date: 4 Jan 90 13:46:55 GMT
References: <MZb4w2600WB88M=4wv@andrew.cmu.edu>
Organization: AT&T Bell Laboratories
Lines: 41

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