OSA Link Cable Schach computer

Posted on Feb 6, 2014

The SciSys Leonardo and Saitek Galileo and Renaissance chess computers could be connected to a PC via an OSA-Link cable. Such a cable is needed to run the OSA-4-Arena software and other tools. Unfortunately that cable is no longer available. Special information can be found in the manual `Connection Cable for Leonardo Chess Computer`, published fr

OSA Link Cable Schach computer
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om Saitek in 1987. It is available as download at look under Documentations and Saitek. The pictures above are taken from this specification. On the PC side (right) only GNG, RxD and TxD are connected. The OSA interface (left) has GND, RxD, TxD, 5V (regulated) and 9V (unregulated). Both voltages are needed by the TTL-RS232 converter MC1488P. The IC on the left (yellow circle) is a regulator for the 9V from the OSA interface. The next picture shows the original circuit diagram. Is is relative easy to re-assemble an OSA-cable. You will need a modern IC for the TTL-RS232 conversion and two cables, one with a 5-pin-DIN male jack and the other with a 9-pin female RS232 socket. As IC you can take the well known MAX 232 or an ADM232L. Both ICs need only 5V to operate, so the 9V from the board is not needed and will make the work easier. For the ADM232L you will need 5 condensers with 1 F each, that`s all. The IC has two communication lines (T1/R1 and T2/R2), for OSA only one will be used. You can choose any of these ICs and assemble your own circuit, but it will be much easier to buy a ready-to-go assembly kit. A fellow at found a very nice kit at, a german electronic distributor. It is still possible to order the kit from foreign countries. The Sub-D cable is for the connection from the adapter to the PCs serial interface and optional, if you don`t have one. If your PC or Laptop does not have a serial interface, you can use an...

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