- 8. Implementation
- 9. MTAS COMPATIBILITY ISSUES
- PSTN Concerns
- A century after the telephone was introduced
most residential subscribers still have plain old telephone service. They
would not be affected whatsoever by the introduction of the MTAS in any
area because their primary telephone address is not altered by the MTAS.
Accordingly CLASS such as Caller ID, Call Forwarding, Call Block and so
forth, are not affected by MTAS. In this respect MTAS differs most greatly
from the addressing options being considered for the Long Term Numbering
Plan. The compatibility of MTAS with the Long Term Numbering Plan is discussed
in detail in the NANP Expansion
Report issued by INC, which has
been emended for this purpose.
- Special Services
- MTAS is directly compatible with Extended
Emergency Service <911>. As for Fax Routing, a specific MTAS extended-service
marker, for example <#*#>, might indicate that a suffix group
would follow the PSTN address in accordance with the Fax Routing protocol.
- This concept can be carried beyond Fax
routing however, as is illustrated below:
- The final three tones are audible access
signals transmitted after the connection is made to distinguish between
related devices. Using <*##> for example, numerous devices
can be accessed.
- Each different utility would use their
own audible code to access their own metering device.
- Hence MTAS can handle utilities not yet
devised. Of course such addresses would be automatically dialed.
- Of course this same arrangement can be
used for bank branches for example, with special services such as automated
teller machines and terminals accommodated by sub-addresses. Simultaneous
access to multiple terminals could be accommodated by multiplexing. Similarly
with modern supermarkets, which require just about the same special services,
including automated teller machine access.
- It is evident from these example that
any of these special services can be piggybacked on MTAS, whether Universal
Messaging Service, Fax Routing, or any of the acceptable options of the
LTNP. MTAS compatibility is evident because even after MTAS is implemented
in any NPAs it would be invisible until accessed. The presence of MTAS
is imperceivable to all users except those subscribing to its services.
- PBX Concerns
- Only the most recently installed Private
Branch Exchange (PBX) systems have routing and control functions equivalent
to PSTN electronic switching. Although some PBXs recognize <*>
and <#> tones for special services, in general they are simply
plain old telephone exchanges. PBXs would not be compatible with LTNP because
the PBX switches will not be able to recognize a priori whether
the address dialed had one greater or one fewer digit. Consequently LTNP
will require all PBXs to be upgraded before LTNP implementation. This will
not solve the compatibility problem however during the transition period.
In contrast, because MTAS is fully compatible with the present addressing
protocol, PBX systems need only be upgraded at the time MTAS services are
- WATS Concerns
- Incoming Wide Area Telecommunication
Service (WATS) is a reverse-charge billing system not consistent with the
NANP scheme. Although the WATS code <abc> resembles an area code
it has no assigned NPA. Nevertheless, by reprogramming SS7 a billing system
was implemented wherein the call receiver would automatically be billed
for the telephone charge rather than the call originator. In practice an
NANP-wide WATS code <abc> prefixes the telephone address assigned
to the subscriber.
- WATS has become so popular with commercial
firms dealing directly with the public that the originally assigned WATS
code <800> has been essentially filled and two new codes have been
assigned: <877> and <888>, further consuming the available
NANP area codes.
- MTAS would supersede WATS, although preserving
the concept. Instead of a centrally adminstered WATS database a specific
MTAS extended-service marker, for example <###>, would
indicate that there is a toll-free sub-address of a firm's primary telephone
address. For toll-free fax transmission another extended-service marker,
perhaps <##*> could be employed. Unlike WATS codes, the MTAS
area code is fully consistent with the NANP.
- Sub-Address Resolution Concerns
- MTAS permits a very practical means of
transferring to the user the responsibility of resolving the sub-addresses,
thereby relieving the LEC of this responsibility. The required Address
Resolution Device (ARD) would be located at the user's site, with the purchase
and maintenance of the ARD the user's responsibility. If a residential
user has two or more sub-addresses the user could be enticed to acquire
an ARD by the LEC offering a rate discount.
- The ARD, being the responsibility of
the residential subscriber, would be located within any residence beyond
the residential Telephone Network Interface device. If the ARD were located
at the entrance point of the telephone line, it would be convenient to
utility meters, alarm systems, and other special service devices.
- MTAS would be particularly advantageous
to LECs for commercial subscribers as far as resolving sub-addresses are
- All of the addresses and sub-addresses
assigned to any one commercial domain would be bundled at the COX and routed
to that domain. The PBX at that domain would simply route each bundled
sub-address to its assigned user site, relying on the site ARD to resolve
- 10. INTEREXCHANGE COMPETITION