Voxbone announces that its international, geographically-independent number service, iNum, now supports HD voice. iNum adds a missing piece -- a uniform identifier -- to enable HD calling. As long as both endpoints are HD-enabled, calls to iNum numbers will convey a sound quality that far surpasses traditional circuit-switched telephony.

The new capability, announced at the HD Communications Summit in New York, adds the benefit of in-the-room sound quality to iNum's location neutrality and cost savings on international calls.

Prefaced with the ITU-assigned 883 code, iNum numbers refer to the Internet in the same way that 44 refers internationally to the U.K. and 1 refers to the U.S. A call to an iNum number is routed first to Voxbone, which carries it over the expensive, long-distance leg of the route before delivering it to the appropriate service provider, which terminates the call to its subscriber.

A high-definition voice signal cannot fit through the frequency constraints of Plain Old Telephone Service (POTS) -- a fact that limits the HD benefit to end-to-end IP calls. However, most iNum calls should be able to support HD voice because most iNum traffic is transmitted by service providers that have migrated to IP or begun operation as VoIP carriers.

In another scenario, a call-conferencing provider could use iNum for an internationally "local" access number. In-the-room voice quality frequently has been noted for alleviating "ear strain" and improving attentiveness on long conference calls.

Voxbone is beginning its HD support with the wideband G.722 codec and plans to add other codecs in the fourth quarter of this year.