Private branch exchange

FIG. 1 is a front perspective view of a first embodiment of a private branch exchange of the present invention;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a first side view thereof;

FIG. 5 is a second side view thereof;

FIG. 6 is a top view thereof;

FIG. 7 is a bottom view thereof;

FIG. 8 is a front perspective view of a second embodiment of a private branch exchange of the present invention;

FIG. 9 is a front view thereof;

FIG. 10 is a rear view thereof;

FIG. 11 is a first side view thereof;

FIG. 12 is a second side view thereof;

FIG. 13 is a top view thereof; and,

FIG. 14 is a bottom view thereof.

The broken line showing of private branch exchange is included for the purpose of illustrating environment and forms no part of the claimed design.