FIG. 1 is a perspective front view of a first embodiment of an operating unit showing our new and ornamental design,
FIG. 2 is a perspective rear view thereof,
FIG. 3 is a front view thereof,
FIG. 4 is a rear view thereof,
FIG. 5 is a first side view thereof,
FIG. 6 is a second, opposite side view thereof,
FIG. 7 is a first end view thereof; and
FIG. 8 is a second, opposite end view thereof,
FIG. 9 is a perspective front view of a second embodiment of an operating unit showing our new and ornamental design,
FIG. 10 is a perspective rear view thereof,
FIG. 11 is a front view thereof,
FIG. 12 is a rear view thereof,
FIG. 13 is a first side view thereof,
FIG. 14 is a second, opposite side view thereof,
FIG. 15 is a first end view thereof, and
FIG. 16 is a second, opposite end view thereof,
FIG. 17 is a perspective front view of a third embodiment of an operating unit showing our new and ornamental design,
FIG. 18 is a perspective rear view thereof,
FIG. 19 is a front view thereof,
FIG. 20 is a rear view thereof,
FIG. 21 is a first side view thereof,
FIG. 22 is a second, opposite side view thereof,
FIG. 23 is a first end view thereof, and
FIG. 24 is a second, opposite end view thereof,
FIG. 25 is a perspective front view of a fourth embodiment of an operating unit showing our new and ornamental design,
FIG. 26 is a perspective rear view thereof,
FIG. 27 is a front view thereof,
FIG. 28 is a rear view thereof,
FIG. 29 is a first side view thereof,
FIG. 30 is a second, opposite side view thereof,
FIG. 31 is a first end view thereof, and
FIG. 32 is a second, opposite end view thereof,
FIG. 33 is a perspective front view of a fifth embodiment of an operating unit showing our new and ornamental design,
FIG. 34 is a perspective rear view thereof,
FIG. 35 is a front view thereof,
FIG. 36 is a rear view thereof,
FIG. 37 is a first side view thereof,
FIG. 38 is a second, opposite side view thereof,
FIG. 39 is a first end view thereof, and
FIG. 40 is a second, opposite end view thereof,
FIG. 41 is a perspective front view of a sixth embodiment of an operating unit showing our new and ornamental design,
FIG. 42 is a perspective rear view thereof,
FIG. 43 is a front view thereof,
FIG. 44 is a rear view thereof,
FIG. 45 is a first side view thereof,
FIG. 46 is a second, opposite side view thereof,
FIG. 47 is a first end view thereof, and
FIG. 48 is a second, opposite end view thereof,
FIG. 49 is a perspective front view of a seventh embodiment of an operating unit showing our new and ornamental design,
FIG. 50 is a perspective rear view thereof,
FIG. 51 is a front view thereof,
FIG. 52 is a rear view thereof,
FIG. 53 is a first side view thereof,
FIG. 54 is a second, opposite side view thereof,
FIG. 55 is a first end view thereof, and
FIG. 56 is a second, opposite end view thereof,
FIG. 57 is a perspective front view of an eighth embodiment of an operating unit showing our new and ornamental design,
FIG. 58 is a perspective rear view thereof,
FIG. 59 is a front view thereof,
FIG. 60 is a rear view thereof,
FIG. 61 is a first side view thereof,
FIG. 62 is a second, opposite side view thereof,
FIG. 63 is a first end view thereof; and,
FIG. 64 is a second, opposite end view thereof.
The broken lines shown in the drawing views is for the purpose of illustrating environmental structure and forms no part of the claimed design.