Do I have to use the XRX audio connections?

No. XRX will function normally without any audio hookups. The audio hookup simply enables an advisory or alert to be heard through the headset. When XRX determines that a detected aircraft may be close enough to warrant an alert or advisory, an attempt is made to alert the pilot to this impending threat. XRX incorporates two audio systems in order to accomplish this: a headset-direct female voice through a simple headset connection, and a high-pitched tone generator. The voice alert and the tone generator can be used or turned off in any combination. Also, an instant-mute function is available to suppress any audio output.