I decided to change the design of the Retro Adapter V2. Instead of using the centre pins of the DB-25 for extra option “jumpers”, I changed to using a three position switch (on – off – on).
The main reason for doing this is that it frees me from just having to use a DB-25. While it is still the plan to use one, the new design also allows for the use of two DB-9s. Using DB-9s allows the use of two female DB-9s for connecting controllers, as with the DB-25 only moulded ones without screw tabs will fit.
A sub-miniature switch should fit in the enclosure, or could easily be attached to a length of wire or substituted for a pin header and jumpers. It also frees up an extra I/O pin so I decided to attach a dual red/green LED. At the moment there does not seem to be enough space on the board for the two resistors it would need, but I’ll add holes for it anyway in case anyone wants to use an alternative case, or simply attach them underneath the board. The LED currently changes colour depending on the position of the switch.