Optional accessory for the JPL-Explore/JPL-Element-X500 DECT Wireless Headset The JPL-Explore/X500 USB Cartridge Module when used together gives you: PC audio streaming. Softphone interoperability through USB/computer out of the box with Skype for Business and with all other major softphones with assistance from the JPL Gateway. The JPL Gateway offers full functionality between headset and softphone and is available to download from https://www.jpltele.com/resources/jpl-gateway/