Thank you, this version works. :-)
I look forward to and wish you good luck with new programs!
I still wonder why the port 255 reading method is used (originally), I didn't find the reason anywhere in the Timex documentation.
Thanks for letting me know. I'll post a new build once I've retested everything.
According to https://worldofspectrum.org/faq/reference/tmxreference.htm bit 7 controls which memory bank is used. However it's only used to to support cartridges on the TS2068. Bit 6 disables interrupts.