The SRUSB end plate adds a micro USB port for firmware updates to SRc series receivers and earlier model SR series receivers that have been updated for Superslot compatibility. Firmware updates will require Wireless Designer v1.3.9 or higher.
The adapter attaches in the same manner as the audio/power adapters for SRc Series receivers and can be used to update your entire SRc inventory.
Please note: This accessory is only for updating. It does not pass audio via USB and does not allow the receiver to connect with Wireless Designer for scanning or frequency coordination purposes.
For use only with SRc Series Receivers, and earlier model SR Series receivers that have been updated for Superslot compatibility.
See data sheet here