Obviously SIP is considerably better than H.323 and complies with the understanding of IP-telephony as a global mass IP-service, and it should be implicitly considered right this way. And as SIP is able to serve not only telephony but also any communications at all in the real time over the IP-protocol; obviously it should become a base for other IP-services not yet existing but will appear in the future, as well.
Rendez Ltd delivers and supports IP based phone systems exclusively to business customers. We provide SIP Trunks as well as traditional PSTN call traffic and are able to offer these services nationwide.