5. Multifunctional Addressing System
6. SIGNALING AND CONTROL
At present common channel signaling and control is implemented between LECs and between LEC and Interexchange Carriers (IXC) using Signaling System Seven (SS7), a highly sophisticated programmable switching network permitting interconnectivity on a highly intelligent basis using standardized procedures. The SS7 network parallels the audible signal network but functions solely for transmitting routing and identification codes to open and maintain the channel between terminal devices.
 
Because MTAS is strictly an addressing protocol, essentially relabeling addresses, MTAS will be totally compatible with SS7 routing and identification, except that MTAS device address strings are not the same length as telephone addresses, a complication that must be considered.
 
Differentiation between POTS address lengths and MTAS address lengths must be unambiguous in relation to routing and identification. For example consider a local connection between two terminals sharing the same COX using the the present POTS routing and identification.
 

 
Routing and identification are identical for the telephone and for the facsimile connections because POTS address string lengths and arrangements are identical. When the incoming telephone address 321-3456 is recognized to be that of a receiver within the same COX, the COX group 321 is stripped off and line number 3456 sets the switches to complete the circuit between telephone sender 1234 and receiver 3456. Likewise, when the incoming facsimile address 321-4567 is recognized to be that of a receiver within the same COX, the COX group 321 is stripped off and line number 4567 sets the switches to complete the circuit between sender 2345 and receiver 4567. Altogether four telephone addresses were required for these two transactions.
 
Consider now these local two transactions under the MTAS protocol. To eliminate any possibility as to address length ambiguities in signaling and control the following protocol will be mandated.
Hence if the marker group comprises only two symbols such as <**> a dummy tone must be added. Arbitrarily a zero tone will be used for this purpose: <**0>.

Consequently a logic switch must check the tone of each incoming digit and compares that tone with the * and # tone. If there is no match then the string is recognizes as a seven-digit telephone number.

 

 
The logic switch checks the tone of each incoming digit and compares that tone with the * and # tone. If there is no match then the string is recognizes as a seven-digit telephone number. If a * or # symbol tones is recognized in the string then four alphanumerical tones must follow the symbol tone. However if a second symbol tone follows the first symbol tone then four alphanumerical tones must follow the last symbol tone. Accordingly the incoming facsimile address can be recognized as distinct from a telephone address.
 
Because the facsimile address 321 <**> 3456 is recognized to be that of a receiver within the same COX 321, the COX group 321 is stripped off. However only two tones are read before an alphanumerical tone is read. According to the protocol a 0 tone must be suffixed to the symbol pair. The symbol group **0 and the line-number group 3456 are then transposed. The circuit is then completed to the receiver facsimile.

 

 
Accordingly the original POTS facsimile line number of 4567 is replaced by the MTAS 3456**0, which sets the switches to complete the circuit between sender 1234**0 and receiver 3456**0. Altogether just two telephone addresses were required for these two transactions.
 
 
Consider now a call originating in one local exchange and terminating in another.

 
Because the facsimile address 321 <**> 3456 is recognized to be that of a receiver within different COX 321, the COX group 321 is retained. However only two symbol tones are read before an alphanumerical tone is read. According to the protocol a 0 tone must be suffixed to the symbol pair to fix the symbol group to three tones. Although POTS interexchange control strings are fixed at seven digits MTAS interexchange control strings are fixed at ten digits. Consequently the receiving COX 432 must check whether any symbol tones are arriving to determine the length of the incoming string. This 10-digit string is transmitted to COX 432 where COX group 432 is stripped off. The symbol group **0 and the line-number group 5678 are then transposed. The circuit is then completed to the receiver facsimile.
 
Consider now a call originating in one NPA and terminating in another.

 

 
The initial access code indicates to the originating NPA that the terminal device is located in another NPA and therefore the string length is ten digits for POTS and 13 digits for MTAS, depending on wheter symbol tones are embedded. Because the facsimile address (876) 321 <**> 3456 is recognized to be that of a receiver within different NPA 876 by the originating NPA the NPA group 876 is transmitted. However only two symbol tones are read before the line tones are read. According to the protocol a 0 tone must be suffixed to the symbol pair to fix the symbol group to three tones and the string length to 13 digits. This 13-digit string is transmitted to NPA 876 where NPA group 876 is stripped off. Subsequently the receiving NPA 876, ignorant of the length of the string, checks whether any symbol tones are arriving to determine the length of the incoming string: whether seven digits or ten. The 10-digit facsimile string is transmitted to COX 543 where COX group 543 is stripped off. The symbol group **0 and the line-number group 5678 are then transposed. The circuit is then completed to the receiver facsimile.
 
Essentially two telecommunication systems are in operation: POTS and MTAS, but they share the same hardware and are interactive. Accordingly MTAS can be implimented without disturbing POTS. However MTAS is intrinsically more versatile than the present POTS system. Because the symbol group is fixed to three tones therefore three markers can be utilized for special functions.

 

Two symbols would handle all terminal devices which are generally manually dialed. Three symbols would be required for commercial services such as automatic teller machines and credit card validation and residential services such as automatic meter reading. However these latter would rarely, if ever, be manually dialed.

It is apparent that the MTAS can accommodate devices not yet commercially available or even yet devised. When videophones are perceived to be useful to businesses they can be readily accommodated by the MTAS.

Contents

7. PORTABILITY