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From: p6ip329@cicrp.jussieu.fr
Newsgroups: sci.electronics
Subject: ** RS-232 INTERFACE CABLE FOR CASIO **
Date: 4 Jan 1995 08:53:55 GMT
Organization: Magistere d'Informatique Paris 5
Two months ago, I asked here if someone knew how to make a RS232 interface cabl
e
for a casio 8800.I've found in Elektor (July issue, p23) a very simple circuit
to make it for casio's organizer.As casio's interfaces are the same for organiz
ers
and calculators, I think this one would work for my calculator too (I didn't
have the time to make it yet).Here it is:
/\ |\ _____
|| ---- TxD -----| >0------*---|R1 |----------* J2, pin 2 (DB9, RS232)
-- |/ | -----
|| ---- RxD ---\ /| | D1
-- \----0< |--+-----*-----K|-----* J2, pin 3 (DB9, RS232)
|| ---- GND --\ \| |- |
|| \ Z |R2|
---- \ |+ |
| | \---------*-----*------------* J2, pin 5 (DB9, RS232)
|J1|
: :
< _________ < D2
To 4049 VCC *-----*---| 78L05 |-----K|------* J2, pin 4 (DB9, RS232)
| ----+---- |
= C2 | = C1
| | |
*-------*------*----------* J2, pin 5 (DB9, RS232)
|\
---| >0---- = one sixth of 4049
|/
R1 = 470 ohm
R2 = 47K ohm
Z = Zener diode 5.6 V (+ connected to GND, - to R1)
D1 = D2 = 1N4148
C1 = 100 uF, 16V. - connected to GND
C2 = 1 uF, 16V. - connected to GND
J1 = 2.5 mm male stereo jack.
J2 = 9 pin (DB9) female plug (for RS232).
pin assignment: 2=RxD
3=TxD
4=DTR
5=GND
others unused.
This circuit needs less than 10 mA to correctly work.
Any suggestions ?
Willy
-------------------------------------------------------------------------------
Willy TARREAU
Magistere d'Informatique Appliquee d'Ile de France (MIAIF) Paris 5 - Paris 6.
E_Mail: p6ip329@cicrp.jussieu.fr
-------------------------------------------------------------------------------
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