Schneiderware V/24 Interface

The Schneiderware V/24 Interface is a RS232 Interface, published by german magazine CPC Schneider International as part of their Schneiderware DIY series. The plain PCB, or the fully assembled board were also available via mail-order.

The ECB Bus connector of the board is intended to be plugged into the Schneiderware Basisplatine, but it could be also wired directly to the CPCs Expansion Port. The V/24 board additionally requires a Schneiderware Power Supply (or another external power supply with +12V/-12V).

• Schneiderware #3 V/24 (RS232 Interface) (8/1986 pages 70-77, plus correction from 9/1986 page 80)

I/O Ports

Default I/O Addresses are F9E0h-F8E1h and F9ECh-F9EFh (ie. the lowest and highest addresses in the F9E0h-F9EFh region). Alternately, addresses F9E2h-F8E3h and F9E8h-F9EBh (ie. the middle addresses in the F9E0h-F9EFh region) are jumper select-able (intended to allow to connect two RS232 cards to the computer).

Address (default)	Address (alternate)	Usage
F9E0h	F9E2h	Schneiderware V/24 8251 USART chip Data
F9E1h	F9E3h	Schneiderware V/24 8251 USART chip Control
F9ECh	F9E8h	Schneiderware V/24 8253 chip Timer 0 (TX clock)
F9EDh	F9E9h	Schneiderware V/24 8253 chip Timer 1 (RX clock)
F9EEh	F9EAh	Schneiderware V/24 8253 chip Timer 2 (unused)
F9EFh	F9EBh	Schneiderware V/24 8253 chip Timer Control

Caution - The clock source can be jumpered to 2MHz (default), or to 1MHz. Moreover, the handshaking signals (CTS/RTS, DTR/DSR) can be disabled via jumpers. There is no good reason for using the 1MHz setting, nor for disabling handshaking at hardware level - these features are only "good" for provoking compatibility problems with software that expects the jumpers to be set to this or that position.

Pictures

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  V/24 Schematic

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  V/24 (component side)

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  V/24 (solder side)