For the moment, IMO, they're exemplifying how the micro controller and the ROMcode interface to the memory logic.....push a button on the user switch and it signals(through voltage differences) various code API responses that inturn mate with the overlay logic of the memory matrix.

737 as a continuation to 774, they're dealing with the rudimentary elements...A,B,C,D&E where, IMO, they were initially published without the recital of structure.

They added the recitals, see the 12 claims of my prior post dealing with the issue.

a micro controller with an internal (ROM) coupled to the recording
medium and to switch assemblies, as discussed in the Specification at Col.
3, lines 56-65.
b. "means for searching for an end of a last recorded
message" is microcontroller with an internal (ROM) coupled to the
recording medium as discussed in the Specification at Col. 3, lines 56-65
and ColA, lines 55-63. col. 4?
c. "means for identifying a point after the end of the last
recorded message" is a casement containing a microcontroller with an
internal (ROM) coupled to the recording medium and to switch
assemblies, as discussed in the Specification at Col. 3, lines 56-65, Col. 4,
lines 55-63 and Col. 5, lines 9-22.
d. "means for beginning recording" is a casement containing a
microphone, a micro controller with an internal (ROM) coupled to the
recording medium and to switch assemblies, as discussed in the
Specification at Col. 3, lines 56-65.and Col. 4, lines 55-63
e. "sequencing playback means" is a casement containing a
speaker element, micro controller with an internal (ROM) coupled to the
recording medium and to switch assemblies, as discussed in the
Specification at Col. 3, lines 56-65 and Col. 5, lines 9-22.

The above API represents a small fraction of the full API of 445 as an OS....at this stage the ROM disepears.

doni