33. Basic-1 and Basic-2
    ~~~~~~~~~~~~~~~~~~~
In order to be able to check compatibility of programs, you may wish to
retain the BASIC-1 ROM in your machine after obtaining BASIC-2. Simply put
the old ROM in a lower-priority ROM socket, and switch to it when required
with *FX142,n  where 'n' is the socket number, (0 to 15). If you have a
program in memory, then type OLD to recover it. Pressing <Break> will not
cancel the change, but switching the machine off, pressing <Ctrl><Break>, or
typing *BASIC will return to BASIC-2. Alternatively, you can use *FX142 to
switch back to BASIC-2.