Prolog STD-7605-0 Prolog STD-7605-0 and STD-7605-1 are the same card except for different chips for input and output, to provide for either inverted or non-inverted inputs and outputs. The 7605-0 board in the photo above has socketed 74LS240 and 7406 chips. the -1 version would have 74LS244 and 7407 chips instead.

Converting the board between the 7605-0 and 7605-1 should be possible by changing the chips, no PC board changes are needed. This is easier if the chips are socketed of course.

STD-7605-0 has I/O ports which use 74LS240 for inputs, and 7406 for outputs. Prolog calls this "inverting I/O" or "low level I/O". A logic 1 written for output produces a "low" output; a high level on input registers as a logic 0 when read.

STD-7605-1 has I/O ports which use 74LS244 for inputs, and 7407 for outputs. Prolog calls this "NONinverting I/O" or "high level I/O. A logic 1 written for output produces a "high" output; a high level on input registers as a logic 1 when read.

See the 64-page ProLog STD 7605 User's Manual documentation for a schematic and board layout to identify the specific ICs for each port. The manual describes the board and the differences between the 7605-0 and the 7605-1. We can offer a photocopy of the manual for 20 cents per page plus postage and handling. In the USA that would be $13 for the copy plus $5 for first-class postage and handling.

Note: the above information is to my best knowledge and experience, but it is offered without warranty of any kind. Use this information entirely at your own risk. Consult ProLog documentation and make your own decisions accordingly. - Herb Johnson