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/* Intro */
This interface was originally described in the book "[[Maschinenspracheprogramme und Hardware-Erweiterungen für Schneider CPC's]]" written by [[Paul Bauriedl]], released by IDEA Verlag in 1987. Around mid-nineties, Tim Riemann has circulated the schematic as GIF in the internet.
The circuit is nearly indentical to the [[Schneider RS232 Interface]] from 1985, both circuits are using a [[Media:Mostek_3801_Data.pdf|Z80 STI]], both mapped to the same I/O port addresses. Both circuits seem to be are driven by the 4MHz signal on the CPC's expansion port, so even and connect CTS/RTS/DSR/DTR to the the timings should be same pins, so they are (almost) 100% compatible. Some differences:* The only difference is that the DIY Schneider circuit uses more logic chips for decoding of the I/O port addresses (the extra chips are just more over-complicated, not actually better)additionally implements CHRDET. Another difference, concerning the power supply, is that the * The Schneider circuit contains 2 diodes and 2 diodes for converting ~7V 8V AC to +/-7V 8V DC.* The Schneider circuit uses only 2 chips for port decoding (the overcomplicated DIY uses 5 chips for exactly the same purpose)
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