Check the listing for details. Aiphone AX-084C Central Exchange Unit 8-Door Master AX Video Intercom System. Condition: New. Listed at 899.00 USD. The AX-084C is a Central Exchange Unit for the AX Integrated Audio & Video Security system. Audio/ Video and/ or Audio-only Master or Door Stations connect directly to this unit via homerun CAT-5e wiring and RJ45 jacks.The AX-084C supports up to 4 Master Stations and up to 8 Door/ Sub stations. The AX-084C can be expanded in increments of 32 for up to 104 Door/ Sub stations with the use of AX-320C add-on CEU's. The CEU handles the calling and communication signals for the system, as well as providing selective door release outputs, video outputs, DVR trigger outputs, and CO line transfer output.System set-up and a variety of functions are programmed in the CEU with the use of the supplied software. Power is applied directly to the CEU via two PS-2420UL power supplies. The serial connection is for uploading the system programming, for raw RS232 data output, or for system monitoring via the supplied program.