Endpoint Manager and Cisco 79x5 with the 7916 key expansion module

I’m not aware of the SIP version of the 79xx phones supporting sidecars under any configuration. In SCCP mode, I’ve used this sidecar and I know it’s supported.

If you haven’t already done a lot of work to get that phone working in SIP mode, I’d recommend using Chan-SCCP-B for the sidecar support.