MOBILE STATION FEATURES

An MS feature is defined as a piece of equipment or a function which relates directly to the operation of the MS.

TYPES OF MS FEATURES

MS features are defined as mandatory or optional. Mandatory features must be implemented as long as they pertain to the MS type. The choice of implementing optional features is left up to the manufacturers. Manufacturers are responsible for ensuring that the MS features neither conflict with the air interface nor interfere with the network, any other MS, or the MS itself. Standardization of a minimum set of features is desirable to make a simple and uniform set of MS features independent of the MS manufacturer and type. This minimum set includes all the mandatory features.

There are three categories of MS features:

• Basic:

Basic MS features are directly related to the operation of basic telecommunication services. Each feature is classed as being mandatory or optional.

• Supplementary:

A supplementary MS feature is directly related to the operation of the supplementary service (e.g. display of calling line number). All supplementary MS features are optional.

• Additional:

Additional features are neither basic nor supplementary. All additional MS features are optional.

BASIC MOBILE STATION FEATURES

Mandatory

Display of called number:

This feature enables the caller to check that the selected number is correct before call set-up.

Dual Tone Multi Frequency function (DTMF):

The MS must be able to send DTMF tones. There is special function in MSC to generate DTMF tones. MS just sends a digital signal to this function in MSC.

Indication of call progress signals:

Indications are given such as tones, recorded messages or a visual display based on signaling information returned from the PLMN. On data calls, this information may be signaled to the Data Terminating Equipment (DTE).

Country/PLMN indication:

The country/PLMN indicator shows in which GSM/PLMN the MS is currently registered. This indicator is necessary so that the user knows when roaming is taking place and that the choice of PLMN is correct. Both the country and PLMN are indicated. When more than one GSM/PLMN is available in a given area this information is indicated.

Country/PLMN selection:

If more than one GSM/PLMN is available, the user must have the ability to select their preferred choice.

Service indicator:

The user is informed that there is adequate signal strength (as far as can be judged from the received signal) to allow a call to be made and that the MS has successfully registered on the selected PLMN. This can be combined with the Country/PLMN Selection.

Subscription identity management:

The IMSI is part of the SIM card and is physically secured and standardized in the GSM system. If the user can remove the SIM, its removal detaches the MS from the network causing a call in progress to be terminated, and preventing the initiation of further calls (except emergency calls).

International Mobile station Equipment Identity (IMEI):

Each MS must have a unique identity and must transmit this if requested by the PLMN. The IMEI is incorporated into a module which is built into the MS and is physically secured. The of each individual module is to be carried out by the manufacturer.

Support of A5/1 and A5/2:

Provisions are made for support of up to seven algorithms as well as the support of ‘no encryption’. It is mandatory for A5/1 and A5/2 and non encrypted mode to be implemented, but other algorithms are optional.

Short message indication and acknowledgment:

This feature allows delivery of short messages to a MS from a service center. Such messages are submitted to the service center by a telecommunications network user who can also request information on the message status from the service center. The service center then transmits the message to the active MS user. The MS must therefore provide an indication to the user that a message has been received from the service center and must also send an acknowledgment signal to the PLMN, to show that this indication has been activated. The PLMN then returns this acknowledgment to the service center.

Short message overflow indication:

An MS user using the short message service will be informed when an incoming message cannot be received due to insufficient memory.

Emergency call capabilities:

It must be possible to make an emergency call even without a valid SIM.

Optional

On/Off switch:

The MS can be equipped with the means of switching its power supply on and off. Switch-off is generally “soft”, so that the MS completes housekeeping functions, such as deregistration, before actually switching off.

Keypad:

A physical means of entering numbers, generally in accordance with the layout below:

Keypad

DTE/DCE interface:

This is a standard connector for attaching Data Terminating Equipment (DTE)/Data Communication Equipment (DCE) to an MS and is used with data services.

ISDN ’S’ terminal interface:

A standard connector for attaching equipment to ISDN.

International access function ( ‘+’ key):

This enables a direct, standard method of gaining international access. For this purpose, the MS may have a key whose primary or secondary function is marked “+”. This has the effect of generating the International Access Code (IAC) in the network. This is useful because the IAC varies from country to country and may be unknown by a subscriber who is roaming internationally.

Short Message Service Cell Broadcast (SMSCB) screening:

This feature enables the user of the MS to receive only those broadcast messages that are of interest to the user and in this way save on consumption of battery power. This may be useful in the future to ignore advertisements sent as short messages.

SUPPLEMENTARY MOBILE STATION FEATURES

Charge indication:

This feature enables the display of charging information provided by the PLMN on a per call basis.

Control of Supplementary Services:

It is mandatory that Supplementary Services can be controlled from the MS.

ADDITIONAL MOBILE STATION FEATURES

Abbreviated dialing:

The feature stores a full directory number or part of a directory number in the MS with the abbreviated address. After retrieval, the directory number may appear on the display. An incomplete directory number must be supplemented by means of the keypad function or a second stored number. The full directory number is then transmitted on the radio path.

Fixed number dialing:

Using this feature in conjunction with an electronic lock makes it possible to place a bar on calling any numbers other than those pre-programmed into the MS. There are two sub-categories to this service:

• All calls are made to only one predetermined number.

• Calls can be made to several predetermined numbers. The required number is selected by means of an abbreviated address code.

Sub-addresses may be added to the predetermined number. In both cases, the actual directory number is transmitted on the radio path.

Barring of outgoing calls:

This feature allows outgoing calls to be blocked with the exception of emergency calls. The barring condition may be activated/deactivated by using a key word. The barring may be selective, that is, applied to individual services, individual call types (e.g. long distance, international calls) or supplementary services. No network signaling is involved.

DTMF control digits separator:

This enables subscribers to enter DTMF digits with a telephone number. When the called party answers, the ME automatically sends the DTMF digits to the network after a delay of three seconds. This may be useful for accessing a voice mailbox, when the subscriber knows the actions which they wish to perform. For example, the sequence 087 5551234#31 may dial the mailbox (087 5551234) access menu 3 and delete message 1.

Call charge units meter:

The MS may incorporate a call charge units indicator. This call charge indicator gives information about the actual call charge units consumed during the last conversation or information about accumulated call charge units for each PLMN.

Selection of directory number in short messages:

The short message (point-to-point mobile-terminated or mobile-originated, or cell broadcast) can be used to convey a directory number which the receiver wishes to call. This can be indicated by enclosing the directory number in a pair of inverted commas (“ “). If the displayed message contains these characters enclosing a directory number then a call can be set up. The message can contain more than one directory number, in which case the receiver selects the desired one. This service is useful for giving someone a telephone number via SMS.

Last numbers dialed (LND):

The MS can store the last ‘N’ numbers dialed in the SIM and/or the ME. ‘N’ can take the value up to 10 in the SIM but there is a greater number storage capacity in the ME.