i spend considerable time explaining/correcting wrong views/etc about this. It would sure be nice if this artificial limitation could go away and we could get back to promoting snom benefits instead. ;-)
Yes, snom ONE will allow a limited number of non snom devices as endpoints. Main limitations: no auto provision and no sip REFER(ie=transfer using phone button, but you CAN use *77[ext#])
The reason for this is to allow things like door phones, wifi sip phones, softphones, fxs etc that snom does not make and to accomodate non snom handsets that already exist in clients possesion till they can switch to snom.