1. Dialling, Numbering & Addressing
Pieter der Kruyff
R&S BICK Mobilfunk GmbH

2. Dialling & Man Machine Interface (MMI) Addresses and Identities
Agenda
Definition of terms
Dialling & Man Machine Interface (MMI)
Addresses and Identities
Numbering and Addressing
Call Scenarios

3. Definition of terms (as used in this presentation)
DIALLING - Identity exchange mechanism
between User and Terminal
NUMBERING - decimal representation of
air-interface addresses as seen by the user
i.e. user visible numbering
A Dialling is ID exchange between the user and his/ her terminal. It is the process where user inputs (or selects) the number of the calling party. There are three basic types of dialling methods i.e.
full dialling, or
various types of short dialling of users in own network, or
other methods supported by an application (local or remote), e.g. scrolling and clicking a number from an address book, single key dialling, etc.
B Numbering - decimal representation of users' addresses. Numbers are decimal digits visible to and dialled by the user in order to set up a call with the called party.
C Addressing - ID exchange mechanism over air-interface, provides the routing information to the transit network about destination of the calling party.
ADDRESSING - Identity exchange
mechanism over air- interface

4. ID exchange between user and terminal
TETRA Dialling & MMI
ID exchange between user and terminal
Leading Digit dialling - ETR 300-5
Display scrolling
Number presentation (CLI & TPI)
with mnemonics
Soft keys
Special numbers e.g. 999/ 112
ETR recommends a method for leading digit dialling
ETR 294 provides guidelines for the MMI
Mode keys
Full dialling
Man-Machine Interface MMI - ETR 294

5. TETRA Addressing MOBILE NETWORK ID SHORT SUBSCRIBER ID
24 BINARY BITS
SHORT SUBSCRIBER
IDENTITY
(SSI)
MOBILE
COUNTRY
CODE
(MCC)
NETWORK
(MNC)
TSI - TETRA Subscriber Address/ Identity comprises of:
Mobile Network Identity MNI (24 binary bits) comprising of:
MCC Mobile Country Code
10 binary bits (ADDRESSING)
maximal/ recommended decimal value / 999
MNC Mobile Network Code - 14 binary bits
maximal/ recommended decimal value 16,384 / 9,999
Short Subscriber Identity SSI (24 binary bits)
max./ recommended decimal value 16,777,215 / 9,999,999
24 BINARY BITS
7/8 DECIMAL DIGITS
10 BITS
3/4 DIGITS
14 BITS
4/5 DIGITS

6. Family of TETRA Addresses
(ITSI) INDIVIDUAL TETRA SUBSCRIBER IDENTITY
(GTSIs) GROUP TETRA SUBSCRIBER IDENTITIES
(ATSI) ALIAS TETRA SUBSCRIBER IDENTITY
TETRA Terminal or Subscriber can have several Identities - a family of TSIs
Individual TETRA Subscriber Identity ITSI
Alias TETRA Subscriber Identity ATSI
Group TETRA Subscriber Identities GTSIs
One or more TSI visiting Families can coexist (be bound with) the home TSI Family
HOME NETWORK
(V)ATSI VISITING ALIAS TETRA SUBSCRIBER IDENTITY
(V)GTSIs VISITING GROUP TETRA SUBSCRIBER IDENTITIES
VISITING NETWORK

7. X.121 E.212 TETRA Addressing Plan ITU Recommendation X.121
Numbering Plan for Data Networks
E.212
ITU Recommendation E.212
Numbering Plan for Public Land Mobile Terminals, e.g. GSM
The structure and numbering of TETRA address ITSI is very similar to E.212 address for GSM which is called an IMSI,in that both have 3 fields, a Country Code field, a mobile network field and a subscriber element.
The subscriber element field in E.212 is referred to as an MSIN, whilst in TETRA it is referred to as a SSI. Though similar in structure the length of the individual fields in each structure is different. A further difference is that TETRA standards allow the ITSI to be dialled within a TETRA environment. This is not recommended for the IMSI in ITU Recommendation E.212.

8. Numbering & Addressing
Numbering and Addressing Plans
Basic Numbering
Enhanced Numbering
Leading Digit Dialling
4 Scenarios
Home & Foreign Network
PABX & E.164

9. Linking TETRA Addressing & Numbering
3/4 DIGITS
4/5 DIGITS
7 / 8 DECIMAL DIGITS
TETRA NUMBER
SHORT SUBSCRIBER
IDENTITY
(SSI)
MOBILE
COUNTRY
CODE
(MCC)
NETWORK
(MNC)
TSI - TETRA Subscriber Address/ Identity comprises of:
Mobile Network Identity MNI (24 binary bits) comprising of:
MCC Mobile Country Code
10 binary bits ADDRESS, dialled as
maximal/ recommended decimal value / 999
MNC Mobile Network Code
14 binary bits ADDRESS, dialled as
maximal/ recommended decimal value 16,384 / 9,999
Short Subscriber Identity SSI
24 binary bits ADDRESS, dialled as
max./ recommended decimal values 16,777,215 / 9,999,999
TETRA ADDRESS

10. How many numbers for a TETRA Terminal?
One Family of Home Network TSIs
One Individual TETRA Number ITSI
One Alias of individual Number ATSI
One or more TETRA Group Numbers GTSIs
One or more Families of Visiting Network TSIs
Unassigned SSI (USSI)
One Visiting Alias (V)ATSI
One or more Visiting Group Numbers (V)GTSIs
One telephone number E.164.

11. Communication within home TETRA Network
Basic TETRA Number
Communication within home TETRA Network
No need for algorithm selection
Home dialling algorithm applies
decimal value range from 0 to 16,777,215 (224)
User may dial between 1 and 8 digits
7 digit with max value recommended
Decimal digits are converted to binary SSI
Incorrect numbers are rejected.

12. Enhanced TETRA Numbering
Communication beyond home TETRA Network e.g. another TETRA, PABX, PSTN, ISDN
Need for algorithm selection
Selection of Dialling Plan
Direct number entry via keypad, Mode selection buttons, Soft key menu selection, Leading Digit Dialling
DTMF can be used to access services outside TETRA networks.

13. Leading Digit Dialling
Leading Digit Dialling is the only dialling algorithm selection defined in ETR 300-5
Recommended way to achieve commonality between manufacturers’ implementations
Predefined value for E.164 gateway access is 16,777,184
Predefined value for ISDN gateway access is 16,777,185
14 more values reserved for future use.

14. Call Scenarios
Call originating and terminating on same Network,
Call originating and terminating on different Networks
Calls between TETRA and PABX
Calls between TETRA and E.164 (PSTN, GSM, TETRA!)

15. Scenario 1 - Home Network
9 2
MNC
MCC
SSI
TETRA
Communication within one TETRA Network
No need for algorithm selection
Home dialling algorithm applies, viz.
decimal value range from 0 to 16,777,215 (224 binary)
User may dial between 1 and 8 digits
7 digit with max value recommended
Decimal digits are converted to binary SSI
Incorrect numbers are rejected 1
MNC
MCC
SSI

16. Scenario 2 - Foreign TETRA Net
TETRA (UK)
ISI
MCC
MNC
SSI
To address a user in another TETRA Network in the same country user needs to dial network code MNC and subscriber number SSI.
To address a user in a foreign TETRA Network user needs to dial country code MCC, network code MNC and subscriber number SSI.
ISI
TETRA (UK)
ISI
MCC
MNC
SSI
TETRA (France)

17. Scenario 3 - PABX TETRA (A) TETRA (B ) ISI PABX GW MNI SSI
PABX Subscriber
Number (24 digits)
TETRA (A)
TETRA (B )
ISI
PABX GW
PABX (A)
PABX GW
PABX (B)
To address a PABX subscriber of a PABX in the home TETRA Network the user needs to dial the subscriber number and address it to the PABX gateway.
To address a PABX subscriber of a PABX in another TETRA Network the user needs to dial the subscriber number and address it to the PABX in the other TETRA network additionally using the network code MNC and eventually the country code MCC.
For dialling a PABX extension user may dial up to max of 24 decimal digits, depending on the rules, though typically it would only be 3 or 4.
In reverse direction the PABX user dials TETRA user number which consists of PABX gateway address followed by the TETRA user SSI.
Erroneous numbers are rejected, either by local terminal application or by the Network, depending whether they are incomplete or incorrect .

18. Scenario 4 - E.164 (PSTN, GSM) TETRA (UK) TETRA (Germany)
ISI
E.164 GW
MNI
SSI
External Subscriber
Number (24 digits)
E.164 GW
E.164 GW
Depending on subscription, the user has a choice of dialling E.164 number using the E.164 Gateway which may be located in terminal’s home network or outside it. If inside the home network, i.e.. the MNI is same, then only the SSI needs to be sent to address the E.164 gateway. In case where terminals are sourced from several manufacturers the Leading Digit Dialling with predefined E.164 value for gateway access would ensure common approach.
If the E.164 Gateway through which the call wants to be made is outside home TETRA network, then the MNI identifying the “foreign” TETRA network as well as the SSI addressing the E.164 gateway needs to be sent.
In case of Two-stage dialling, TETRA user dials the E.164 gateway in the same way as above. In response to a dialling tone, or dial-now message, user dials extension number which is encoded at the E.164 gateway into DTMF tones and forwarded. In reverse direction, an E.164 subscriber dials the gateway as another subscriber. In response to a dialling tone, or dial-now message, user dials an extension number which is encoded at the E.164 gateway into a SSI and forwarded to one TETRA user (ITSI), or more TETRA users (GTSI) at the same time in case the E.164 user wants to be involved in a group call.
In reverse direction the E.164 user dials TETRA E164 number which at the gateway is converted into SSI and, if appropriate, MNI. Alternatively, in a two stage dialling user dials TETRA access number followed by TETRA SSI or even MNI and SSI.
E.164 (PSTN, GSM)
E.164 GW
MNI
SSI
E.164 Subscriber
Number (24 digits)
UK Phone
German Phone

19. TETRA IP
TETRA uses IP numbers in the same way as any other IP network
Individual TETRA user can have a fixed IP number or the number can be allocated dynamically
In order to do the air interface signalling, TETRA IP numbers need to be mapped to TETRA ITSIs

20. Conclusions
TETRA dialling plans provide the benefits of flexibility and interoperability to meet the huge variety of needs of professional users
TETRA numbering plans have flexibility to efficiently deal both with simple fleet numbers & full E.164 international numbers
TETRA addressing alignment allows for future interoperability/ roaming with GSM