Sistema de comunicación de alta fidelidad. Soporta la conexión de microfonos locales y remotos. Telefono local y telefono para bomberos.
 
3-ASU/FT* Audio Source Unit with local microphone and firefighters’ telephone
3-ASU/4* Audio Source Unit with local microphone (provides four local rail spaces)
3-ASU* Audio Source Unit with local microphone and inner door filler plate
3-FTCU* Firefighters’ Telephone Control Unit with inner door filler plate
3-ASUMX/100* Audio Source Unit Memory Expansion (100 minutes of message time)
3-CCI City of Chicago Interface