41CL MMU disabled when unplugging serial cable

[rprosperi]

Unplug the serial cable from the PC before you unplug it from the 41CL. The tip is positive and when it is removed, if active due to being plugged-in, effectively shorts the bus (definitely not the correct terminology here) and disables the MMU. This is stated in the manual, but I too never found it and inquired here years ago when this was happening to me.

TL;DR - Unplug the serial cable from the PC first, and then you can unplug it from the CL without resetting the MMU. A common conclusion is it's easier to type XEQ "MMUEN" than trace the cord and unplug it from the PC...