ERA-DCKIT-2 
Although the available sounds may be different on the LRA & ERA receivers, the concept of using a different sound for each zone is the same. Although not mandatory, a different sound is useful to determine which transmitter or sensor triggered the receiver.
Push Button 1 is programmed to Zone 1 on Receivers A, B, C, and D (each of the four offices has its receiver). When someone presses push button #1, it will trigger receivers A, B, C, and D to play the "Ding-Dong" sound.So each office doorbell with its receiver will hear "Ding-Dong" and know it is for the front door.
Push Button 2 is programmed to Zone 2 on Receivers A, B, C, and D (each of the four offices has its receiver). When someone presses push button #2, it will trigger receivers A, B, C, and D to play the "Westminster" sound. So each office with its receiver will hear "Westminster" and know it is for the back door (push button #2).
Push Button 3 is programmed to Zone 3 on Receivers A, B, C, and D (each of the four offices has its receiver). When someone presses push button #3, it will trigger receivers A, B, C, and D to play the "Car Horn" sound. So each office with its receiver will hear the "Car Horn sound" and know it is for side door 1 (push button #3).
Push Button 4 is programmed to Zone 4 on Receivers A, B, C, and D (each of the four offices has its receiver). When someone presses push button #4, it will trigger receivers A, B, C, and D to play the "Siren" sound. So each office with its receiver will hear a "Siren sound" and know it is for side door 2 (push button #4).