All ABUS products are compatible with other ABUS products, it would just depend on the application you are attempting and potentially modifying the position and/or wiring of the system. The AB-901 is a single source 4 zone kit. The AB-404 that comes with that system has an expansion output. You can use this output to then go into the ABUS audio input of the unit that comes with the AB-907 kit , the AB-203. This would allow you to expand from 4 to 5 zones of distributed audio. Now normally if you just used the AB-907W kit by itself the Bluetooth module that comes with it would go into the ABUS audio input, however since that would be used, you would instead run the Bluetooth as a “local” source, this means on the cat5 run on the way to the amplified keypad you would go to the AB-303 input, then use a short Cat5 patch cable from the output and into the input of the AB-134W. When installed in this way the Bluetooth will then override the main audio source (coming from the AB-404) for that zone.