Regarding Skype for Business Online, On-Prem and Hybrid. Are the following services not available by default when using SFBO (all by itself) ? or do the limitations only come into play in a Hybrid Scenario?
Enhanced 9-1-1, the service used for making emergency phone calls.
Call parking, the service that enables users to place a call on hold phone A, then retrieve that call from phone B.
Media bypass, which enables calls to and from the public switched telephone network (PSTN) to bypass the Mediation server, helping to minimize transcoding and network latency.
PSTN conferencing dial-in and dial-out, which enables users to participate in the audio portion of an online conference by using any PSTN telephone or mobile device.
It would seem to me that users homed online, have a much more limited feature set than users homed in SFB on Prem? I am hoping someone who has worked with SFBO Hybrid/On-Prem can assist and kinda of explain how this all might work.
I'm not very familiar with the hybrid voice scenario, but I can answer these questions in the context of using Skype for Business Online with Phone System in a non-hybrid configuration.
By Enhanced 9-1-1 I'm assuming you are referring to the service that transmits the caller's address to the 911 dispatcher. Skype for Business Online does in fact require you to specify an emergency address for each PSTN number you assign.
Call Park is not available with SfBO. (However, it has recently been added to Microsoft Teams as documented here.)
Media bypass is not applicable as all PSTN calls go through Microsoft's servers. (If you are wondering about the hybrid scenario, that is documented here.)
PSTN conferencing is available. (Depending on which Office 365 plan your users have, it may require purchasing the Audio Conferencing add-on license for your meeting organizers.)