From HME's IC300 to 3M's D20 Intercom these products will keep you up and running.
HME IC300 Intercom
The HME IC300 Intercom is a rugged, cost-effective intercom that is great for low volume drive-thru's or as a backup for your wireless headset system. This unit features a day and night switch with voume controls, a splash-risistant keypad and case, and an alert with an led indicator to let you when a car is there. This easy to use unit could be the intercom solution you are looking for.
3M D15 Intercom
The 3M D15 Intercom has a single station application. This unit features touch panel switches and indicator lights for power-on, standby, presence alert, talk and listen. This unit will help provide clear, convenient and reliable communication.