From: p6ip329@cicrp.jussieu.frNewsgroups: sci.electronicsSubject: ** RS-232 INTERFACE CABLE FOR CASIO **Date: 4 Jan 1995 08:53:55 GMTOrganization: Magistere d'Informatique Paris 5Two months ago, I asked here if someone knew how to make a RS232 interface cablefor a casio 8800.I've found in Elektor (July issue, p23) a very simple circuitto make it for casio's organizer.As casio's interfaces are the same for organizersand calculators, I think this one would work for my calculator too (I didn'thave 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 TARREAUMagistere d'Informatique Appliquee d'Ile de France (MIAIF) Paris 5 - Paris 6.E_Mail: p6ip329@cicrp.jussieu.fr-------------------------------------------------------------------------------