Hello! I'm looking at advanced phone systems for a future small business but I'd like to clarify some of the system names/terms used, to know exactly what I need to search for, as I'm feeling a bit confused. My current understanding is that advanced systems are or were called PBX systems and used to be physically based until the cloud movement we see today, the term IVR is for menus, VOIP is a broad term for voice calls over the internet like Skype, and f knows on many of the other terms like SIP Trunking. There are now many terms floating around for cloud based equivilents. I'm looking at advanced systems with things like menus/IVR and greeting/hold messages, call recording, diverting to other numbers/voicemail/out of office messages during certain days/times, transferring to others, calling other internal phones, listening in to a call/monitoring, logging, picking up the call from another ringing phone, maybe being able to use an app or another way to make/recieve calls from a mobile, etc. What exactly am I looking for please, in terms of what do I search/ask for? I'm also happy to take any recommendations of brands/services. Thanks.