With the ever increasing use of telphone numbers in devices such as garage door openers, security systems, and truly universal remotes, there will soon be a shortage of telephone numbers.
While there are certain extensions that are reserved for various protocols, such as #80 for WvT (Web via Telephone), #25 for t-mail or #161 for STMP (simple telephone management protocol), the high extensions are available for call forwarding.
TNT (telephone number translation) can solve these problems. TNT allows telephones to share the same phone number. When a telephone dials out to a remote telephone, the TNT server opens a high extension dynamically. When calls are returned from the remote telephone, the call is automatically forwarded to the original caller.
Telephones will be assigned a dynamic virtual phone number from the pool (192) 168-0000 to (192) 168-9999. This will be accomplished using a DTCP (dynamic telephone configuration protocol) server. Most VoIP phones request a configuration file from a TFTP server. The TFTP server would be modified to hand out telephone numbers out of a pool. There will be no stable way of querying the telphone number of each phone, but a leases file will be written every so often.
For those technically elite customers that want to receive calls that they did not specifically request, a system of dyanamic DNS would be needed. Normal uses cannot be expected to remember complicated telephone numbers and extensions. Simpler names like john.doe.com would map to a telephone number like (800) 555-1212 ext #1921680015.
Customers requiring secure communications may wish to research VPTE (virtual private telephone exchange).