this sort of systems are very own and employed by the company in place of a telephone corporation. the phone can only be the supplier or provider company of such products.
PBX systems permit conference phone calls. https://laytnebfs244894.blogofoto.com/60764308/top-latest-five-ip-pbx-dubai-voip-pbx-pbx-supplier-in-dubai-ip-pbx-system-dubai-urban-news