Voxbone made a series of enhancements to iNum, its global phone number service. The enhancements include support for presence, enabling iNum users to tell instantly whether fellow iNum users are available on their VoIP phone or instant-messaging client.

iNum uses numbers from the International Telecommunication Union’s new +883 country code, so users maintain a single phone number no matter where in the world they are. The new enhancements expand that reachability by adding presence: iNum users now can tell at a glance whether a contact is best reached by phone or by IM.

The enhancements also include support for cross-client messaging, starting with Google Talk. This new feature initially allows Google Talk users to dial and send IMs to any iNum number for free. Voxbone partners will be adding this functionality so that a customer of one provider can IM an associate who uses another provider to see if she has time for a call.