INDY ME Technical Document INSTALLATION: Call boxes are generally best located at areas that require assistance to access or operate, LE. High shelving, chain and rope cutting, key machine, etc. Stores and installers should be aware of ADA requirements for accessibility. The call boxes utilize a very low powered transmitter, and operate best with a clear line of sight to the nearest receiver, Tall shelving, merchandise and metal signs can block or reduce the caliber signal.