Been there done that, you buy client devices that works well with your server, not the other way around…
You just don’t buy a computer that works well with your keyboard… You know.
Yes Cisco phones are cool, but can sometimes be a pain in the… …to provision with any non Cisco PBX.
We’ve been using Yealink, Polycom, Fanvil, but we now stick to Sangoma Phones. You can literally drop ship these phones and the client can just plug it in… And bingo it works!!
(All you need is getting the MAC addresses from your supplier so you can add them in the redirection portal and EPM)
We use EPM with OBI ATA’s, works great.