The AI-AX-8M is an audio only master station for the AX series. The unit is CAT5e homerun wired to it's CEU and features an oversized TALK button to activate the VOX or PTT style communication, door call-in indicator, call button for other master stations in the system, a call tone volume control and a button for door release. The AX-8M can communicate with 8 masters and 8 door stations. Add-on selectors (AI-AX-16SW) can be added to increase the number of door to a maximum of 120.