Vertical service code

When call processing features (English: supplementary services ), or even just called service features are referred to a public telecommunications network in addition through the network provided subscriber-related services that go beyond the simple connection setup and termination by the caller, the so-called A-subscriber, go to the called subscriber ( B-subscriber ).

Within ISDN ask the local exchanges numerous services that can be used, for example, via an ISDN telephone. Access to and management of services is carried out via keyboard, display and audible tones, the control information is a signaling processes (eg DSS1) exchanged between the terminal and exchange. Such services are also provided participants with other devices (eg analog ). Access to and management of services takes place via the corresponding signaling protocols for these connections.

The call features of public networks can i.250 disaggregated in accordance with their functionality according to ITU -T. While this represents a breakdown was standardized only for ISDN supplementary services, today also features analog and mobile connections and IP telephony are classified accordingly. However, only a subset of the available service features is often supported.

Dividing the features

The following subdivision applies to ITU-T i.250:

Further services

Further services outside of call processing features are part of the above supported intelligent network.

New services outside the ITU- TI.250 specification arise today increasingly used for IP telephony and can be divided into:

• Multimedia services
• Personalized Features

Some service features can be realized in the terminal ( for example, Speed ​​Dial or Call Forwarding in the ISDN terminal ), so that a contribution from the exchange is not necessary even with appropriate instrumentation. In this case we speak of equipment-related features.

Features and their descriptions

The features mentioned below are based on the occurrence in the German-speaking region (Germany, Austria and Switzerland ). Your use and provision is dependent on the network operator.

Transmission of the caller's number ( CLIP)

CLIP ( abbreviation for Calling Line Identification Presentation) is a feature for incoming calls and can be enabled or disabled only on them. In the CLIP number of the calling party is transmitted to the called party, unless this is already restricted on the calling side ( CLIR). Then has the person called a "CLIP -enabled " device is displayed the number of the caller. Does this terminal via an address book with the ability to store names, the corresponding name can be displayed.

The possibility of calling line to the called subscriber was originally only for ISDN available and is available since January 1998 in Germany also for analog telephone lines; in Switzerland. During the call number is transmitted as digital information in the D channel for ISDN connections since 2005, used the time between the first and second ringing signal to transmit the data with analog connections. For a digital FSK signal in the MDMF or SDMF - coding according to V.23 standard is being used. However, the analog terminal must for the evaluation of this signal suitable ( " CLIP " type) to be.

CLIP is referred to by some device manufacturers as CLID (Calling Line Identification).

Suppression of the caller's number ( CLIR)

CLIR ( abbreviation for Calling Line Identification Restriction ) is a feature for outgoing calls, and can be enabled or disabled only on them. With CLIR, it is possible to suppress the transmission of the telephone number to the called subscriber or restrict. It is therefore also known as " CLIR ". It is only to a limited extent, because emergency services police, fire and ambulance services are excluded ( CLIRO ).

The numbers are generally transmitted to the telephone network. Prefer not to a participant, his number is transmitted to the called party, so there is the possibility of the calling number ( CLIR). The called subscriber B can thereby calling A - subscriber is not identified by his phone number, even if he has CLIP activated. In CLIR activated the phone number will be transmitted on the network side to the local exchange of the called party, the called subscriber but not delivered. It is also possible that CLIR occasionally ( to analog phones prefixed by a touch-tone dialing key sequence, on ISDN telephones by means of keypad function ) to activate.

The number suppression following attributes are distinguished:

• Permanent transfer of your own number
• From case to case transmission with continuous suppression
• Conditional suppression with continuous transmission
• Permanent suppression of the call number transfer

Depending on the service provider, all or part of the forms are available.

Ignore the calling number ( CLIRO )

CLIRO ( abbreviation for Calling Line Identification Restriction Override), sometimes also referred to as CLIRIGN ( for Calling Line Identification Restriction Ignore), is a feature for incoming calls and is basically only certain local loops available. It must be unlocked in the local exchange of the called party. With CLIRO an activated CLIR service of the caller 's phone number will be ignored and always transmitted to the called party. This facility is PSAPs police, fire, emergency medical services, and special safety-related connections of the Federal available.

Display the connected line identification ( COLP )

COLP ( abbreviation for Connected Line Identification Presentation) is a feature for outgoing calls, and can be enabled or disabled only on them. When COLP the number of the party accepting the call is demanded by the caller, and transfers as a result backward to the caller ( A-subscriber ). The feature is useful for example when call forwarding: The caller is informed that he has not reached the port that it has chosen, but was diverted to another. However, the called party can by the feature COLR suppress the function of COLP or at least limit, thus preventing the identification of your own number. A limitation exists insofar as PSAPs are exempted police and fire them.

Suppression of the connected line identification ( COLR )

COLR ( abbreviation for Connected Line Identification Restriction ) is a feature for incoming calls and can be enabled or disabled only on them. If COLR is activated, the phone number of the party accepting the call is independent of COLP on the calling side, although transmitted to the telephone network backwards, but it is not for its transmission to the caller ( A-subscriber ). This feature is useful for example when call forwarding: The caller is not informed despite COLP activated, whereas the called party has forwarded his phone. So that the called party has the option restricted to suppress a possibly activated COLP service of the caller and thus protect his privacy.

Transmission customer's own phone number information of the caller ( " CLIP no screening " )

" CLIP no screening " is a feature for outgoing calls, and can be enabled or disabled only on them. In addition to the line-side number ( English network provided ) of the caller can here a self-imposed by the caller custom number ( english user provided, not screened ) can be sent to the called party. No screening in this context means that the caller ID is not checked by the switched telephone network for correctness; they can (TKG and similar regulations in other countries § 66k ) be just another located in the right of use of the caller phone number with some restrictions. To ensure that the service provider is required, ie, must be configurable only by this.

This feature is only available for ISDN connections on the calling side and is only for those on incoming side also apply. The analog lines is - provided CLIR has not been enabled on the calling side - only the network-side phone number is transmitted to the caller, otherwise no.

For example, the caller can suppress its network-based call number using CLIR and send the phone number of a value-added service to the called party.

In general, both numbers of the caller, the network side and the custom (if " CLIP no screening " enabled), transferred in the public telephone network. Capitalised services like CLIP / CLIR on the respective subscriber side and type of connection but decide as to which number is transmitted to the participant. Device-specific settings on the receiver side ultimately decide which number ( or whether both ) are displayed. However, there are not device-specific settings through the type of connection (eg, analog), the display is also clearly defined in this feature.

Display the customer's own phone number of the called party information ( " COLP no screening " )

" COLP no screening " is a feature for accepted calls and can only be disabled for this to enable or. In addition to the line-side number (English " network provided" ) of the party accepting the call can still call a self defined by the Transferee custom phone number (English " user provided, not screened " ) is sent to the caller. " No. screening" in this context means that the caller ID is not checked by the switched telephone network for correctness; they can only be an other in- use right of the calling phone number with restriction. To ensure that the service provider is required, ie, must be configurable only by this.

This feature is only available for ISDN connections on the rufa acquiring side and is only for those on calling page also apply. For analog connection only the network-side number is, was not activated in the event that COLR on the called side, transmitted to the caller, otherwise no.

For example, a participating rufa participants suppress his line-side call by COLR and other custom phone number, for example, the telephone call center or a service number, send the caller.

To display the number same applies as for " CLIP no screening ".

Call back on busy ( CCBS)

With CCBS ( Completion of Calls abbreviation for to Busy Subscriber ) is a caller is able to automate a connection to a previously occupied target participants in the exchange. A caller gets a busy tone from his destination subscriber can activate this service before replacing the handset on the keyboard of his terminal. If the previously busy destination subscriber finishes ( that is, " he hangs up " ), the terminal of the caller gets through the switch information about it. The terminal now signaled to the caller with a special ring ( the recall ) that the destination party is no longer busy. If the caller that callback opposed by picking up the phone, the target user is called again by the exchange. CCBS can not be used when the target person rejects the incoming call or the exchange of the target station does not support the service.

In the Deutsche Telekom network can be used to activate the callback in addition to the tone dialing after the busy signaling since 2005 voice control. The location selected for the previous call attempt Call-by-Call/Preselection-Anbieter is also taken into account when establishing the connection using callback.

CCBS is not the function (automatic ) to confuse re-election of some devices regardless of the telecommunications network, in which in case of a busy tone, the caller device to the destination subscriber repeated calls after a predetermined period of time, until no more busy can be determined, ie the connection of the target subscriber is free again.

Call on No Reply (CCNR )

With CCNR ( Completion of Calls abbreviation for on No Reply ) is a caller is able to automate a connection to a destination subscriber does not answer in the exchange. A caller whose target subscriber is "free" (the call is not answered ), can activate this service before hanging up the phone on the keyboard of his terminal. If the destination user the next time hangs up the phone, the caller receives the terminal through the switch this information. It now indicates to the caller with a special ring ( the recall ) that the target subscriber is available. If the caller that callback opposed by lifting the handset, he is again connected through the switch to the desired destination node.

Call Waiting (CW)

If the call waiting feature (English Call Waiting [CW ] ) is enabled, the participants another incoming call by a call waiting tone is called signaled during an existing connection. The so- informed participant then has the opportunity to accept this second call to ignore or dismiss. To answer the second call, the subscriber may terminate the first connection or allow the feature query, the first connection in the state hold.

Hold, consultation, brokering (HOLD)

The performance hold, switch and inquiries are usually bundled by a central office or PBX feature offered as Call Hold (HOLD).

Hold

By the hold feature, a subscriber can make an existing connection in a standby state. The other party receives in this state usually an announcement or music on hold.

Query

Taking into question the possibility is referred to an existing connection that was previously placed in a wait state with stops to establish a second connection from the same terminal or answer a waiting call.

Brokering

Brokering is a feature in which a subscriber can alternate back and forth between two active compounds. It can talk to each other only the participants of the just existing active connection. The held party is held until the resumption of the discussion at the central office or PBX.

Transfer in office ( ECT)

With the Explicit Call Transfer (ECT ), an existing connection are taught to another subscriber. A connection in HOLD mode is switched together with the active compound, then both external users are connected. However, the connection runs with costs still above the central office of the referring agents.

Three-party conference ( 3PTY )

With the three-party conference service (English Three- Party Conference or Three -way calling ), a conference convener participants, also called initiator, causing a simplified conference call. Here, three participants to each other simultaneously calls, namely everyone with everyone. The three party call is executed by the exchange without the need for a conference call is needed. Participants in a three-way conference must already be connected through switching technology before it can be initiated. This distinguishes it from the actual conference call conference call, which offers additional features and needs.

The difference for the initiator of a three-party conference is that the other two parties must already be connected with him. You must be switched either on hold or on hold and the other in the active conversation. In some mobile networks, participants can also call waiting (Call Waiting) to include in a conference call. However, in the three-party conference, the initiator may never include in the conference more than two other participants.

For ISDN connections, it would be possible to bring about a three-way conference and device technology. However, it would be two B- channels ( for each external conference participants would be required a ) shows instead of just one, as is the case with the switching-oriented three-party conference. Even modern SIP phones have this equipment technical service feature.

Multiple Subscriber Numbers ( MSN) for multipoint connection

With MSN ( English acronym for Multiple Subscriber Number) ISDN Basic Rate Interface can be reached under several phone numbers. The MSNs can be flexibly allocated to the terminal. In Germany the number of MSNs per ISDN multipoint connection is limited by the Federal Network Agency to a maximum of ten. The MSN is the part of the phone number, the area code, also called code, follows.

Terminal Portability (TP ) for multipoint connection

With TP ( English acronym for Terminal Portability ) a call can be parked at the central office and the ISDN terminal to be plugged to another ISDN socket within the S0 bus of the base connection.

Direct Inward Dialing ( DID) for system connection

DDI ( Direct Dialling In English abbreviation for ) (also known as direct inward dialing (DID) known) defines a block of numbers, can be dialed directly by the terminal equipment of a telephone system.

Call Forwarding ( CF and CD)

About the feature Call Forwarding ( Call Diversion English ), an incoming call will be diverted through the switch to a specified number. In this case, no B-channels are assigned to participants, that is, the switching is done directly in the exchange of the callee. For forwarding destination phone number of the original caller ( A-subscriber ) is signaled, but also that of the originally called party ( B-subscriber ). Within such ISDN numbers can be on the forwarding destination also displayed, because the network side, they are always transmitted in the German-speaking countries. However, this does not across national borders and is in part only to a limited extent across network boundaries, such as from a landline to certain mobile networks within Germany. Call Forwarding ( Call Diversion ) is the generic term for various forms of call forwarding and call deflection services (CF or CD):

• For CFU ( abbreviation for Call Forwarding Unconditional ) the redirection takes place in each case immediately - " unconditional call forwarding ".
• In CFB ( English abbreviation for Call Forwarding Busy, GV call forwarding if busy ), the redirection takes place only when the destination station is busy - "Divert if busy".
• In Cfnr ( abbreviation for Call Forwarding on No Reply) the redirection occurs only when the destination subscriber (usually after about 15 seconds) does not answer after a certain time - ' delayed forwarding ".
• With CFDDI ( abbreviation for Call Forwarding Direct Dialing In ) Call Forwarding be fully configured and switched independently of the telephone system to the telephone network. This feature is used in Germany for example, in a system access without cable. CFDDI is a company-specific standard of Siemens, as this type has not been standardized internationally by call forwarding. Accordingly, similar services can also be found with other manufacturers, for example, as CFUWA (CFU on directory number Without Access ) from Alcatel -Lucent.
• In CFVM ( abbreviation for Call Forwarding to Voice Mail), the call is forwarded by the subscriber configurable time-dependent, immediately or if not accessible to the internal network mailbox for the subscriber. This service is mainly used in mobile networks.
• In CFP ( abbreviation for Call Forwarding parallel ) both phones ring simultaneously.
• CD ( English abbreviation for Call Deflection, GV call forwarding after a call offering ( AWS R) ) or Diversion differs from the Call Forwarding services, since the transmission is initiated from case to case ( per call) and not configured to a destination. Call Forwarding and Call Forwarding service features are grouped under the generic term Call Diversion.
• CDO ( abbreviation for Call Diversion Override) allows the suppression of an activated call forwarding or call transfer. This facility is normally private connections are not available.

Call forwarding is thus a vermittlungstechniches feature, since the execution of the service provided by the switching network. In contrast, for providing this service as a technical device feature. By this is meant generally the forwarding on the terminal of the B subscriber. The forwarding destination is outside of your own phone, two B- channels are occupied during the conversation. On the forwarding destination is not the number of the original caller, but the forwarding subscriber B is signaled as a caller.

Partial rerouting (PR ) is available only for ISDN extensions and must be configured and enabled in this. It can be activated for the services CFU, CFB and Cfnr and CD when the forwarding destination takes you back to the public switched network. In this case, when forwarding the sections closing the connection until then built up is achieved within the ISDN extension, so as to occupy any connection channels from the public switched network to the ISDN extension for the duration of a forwarded call.

Transferring ( CT)

With the feature Call Transfer (CT ) can be a dial-up connection to another terminal folded or dial-up connections can be interconnected. The processes are standardized in ITU - T I.252.1

Tariff information ( AOC)

In order to transmit the information on tariffs, there are three options:

• During a call (AOC -D) (English Advice of Charge During Call)
• Before and where appropriate during a call (AOC -S) (only available in a few ISDN networks )

See also: Advice of Charge

Identify ( MCID )

MCID ( abbreviation for Malicious Call Identification) is a service feature for incoming calls and for identifying bell interferers, harassing callers and other offenses intended by phone call ( also known colloquially as the capture or grabber ). The called subscriber can so that the call data of an incoming call is being recorded on the net, and even in spite of an activated number suppression. The call data contain the number of the caller and the called party, time and date. These data, issued by the telephone service provider are accepted as evidence in court. MCID is available in the following forms:

• Identify during an existing call via activation by the called party.
• Identify within a certain time after the end of the call, which requires activation by the called party within 30 seconds after the caller has hung up. Not possible if the called party has hung himself.
• Identify before you take a call ( for the identification of so-called bell interferers ). In general, this is 20 seconds possible after the caller has hung up.
• Automatically identify all unanswered calls.
• Automatic identification of all calls ( answered and unanswered calls).

In Germany the availability of this service feature is required by law and defined deployment and use in the Telecommunications Act ( Germany ). It must be applied generally to the telephone service provider. Gives a Flying Start (or MCID ) usually only in the substantiation of the related criminal or civil legal facts.

§ 101 TKG 2004: Preview incoming connections regulates in detail:

• Providing a grabber and the acceptance of an application
• Information of the detected compounds
• Cross-network information
• Informing the owner of the port of the identified compounds are assumed
• Privacy Legal definitions

Sub-address (SUB )

Subaddress is a subscriber- side extension of the telephone number on the public numbering plan out. This service feature is only available ISDN ports on the calling and the called page. The additional addressing option can be used to target specific devices behind the ISDN user-network interface, for example, to activate an amplifier for an announcement or to start a PC program.

This service feature can only be activated by the network operator. Only the called party needs this permission. Participants dependent activation or deactivation is not provided. SUB can be used in parallel with all other services and does not have different characteristics.

Will participants a participant B to inform A is a Subadressinformation, it sets the so-called Called- subaddress field in his call. This information is then transmitted transparently through the mediating telephone network and subscriber B also delivered with the appropriate authorization.

The maximum length of the subaddress is 20 bytes, so are up to 40 phone numbers transferable. These are dependent on the subscriber coding chosen.

Priority or disaster permission

The feature priority ( Priority English ) is a port - specific service and provides the participants with a higher priority in the switching of calls to and from its local loop. This enables telephoning with overloading of individual exchanges or the entire telephone network. Will use this service, for example at authorities with particular sovereign or security tasks and hospitals. It should ensure their ability to act in emergencies and congestion in the telephone network. This feature is available in three different versions:

• Priority in disasters: This service is only for designated disaster areas to bear. For this purpose, the switch must be placed on the so-called state of emergency, so that these connections get a higher priority in the telephone exchange. The prioritization affects only the local exchange of the terminal and does not apply to the following or preceding that mediation in the telephone network.
• Priority in case of overload: Connections with this value always have a higher priority to and from this port. However, the priority is also effective here, exclusively on the local exchange of the terminal and does not apply to subsequent or preceding that mediation in the telephone network. This priority treatment has a noticeable effect only in the event of an overload the local exchange.
• With priority number Category: Ports with this value to always have an alterable priority switching network. You can still be increased in case of disasters and also has precedence over other priority services and levels. Are a priority identifier is in the so-called number category ( engl. calling party category ) transferred and retains its assigned priority thus in the entire network. It is the premium expression of the service attribute priority. This priority also applies to calls to this port and can already be detected in the local exchange and a caller without priority.

The port priority feature is for analog and ISDN connections. However, the service is not usually obtained for private connections. It requires a special commission by the state. The availability of the feature is required by law in Germany for the public telephone network.

Reject unknown caller (ACR )

With activated Anonymous Call Rejection service feature (ACR ) of the connection request for incoming calls with withheld Calling Line Identification Restriction (CLIR ) is switching- rejected and not put through to the called party. The caller then receives from the central office an announcement; in telecom network, for example, with the misleading text " The person is temporarily unavailable, please try again later ", in which Swisscom with the meaningful text " The Swisscom customer does not want any calls from a withheld number ".

This facility is not actively marketed by most telephone connection providers ( each failed connection means lost revenue), but must due to an EU directive, and translating it into German law ( § 102 paragraph 1 sentence 2 TKG 2007) on request for all ports enabled be. This does not apply to subscriber lines closed user groups.

Call notification ( MWI)

In mobile networks, but also in some fixed networks, there is a grid -supplied by the service provider answering machine (german voice mail system ). Be redirected to this VMS server due to non-availability or non-availability of the callee calls, voice messages can then be deposited to the called party there. Together with the network-side answering a participant usually receives also the switching-oriented service MWI ( Message Wait Indication for abbreviation ). When an incoming voice message is transmitted here the VMS server information to the participant, or its line-side subscriber data. Vermittungstechnisch be transmitted in the entire German -speaking world the message by means of the TCAP protocol. In other countries, such as Italy, which can also be done by an automatic call to participants with over decadal numeric identifier. As the network the information ultimately informs the participants, can be very different and depends on network- as well as device-related characteristics:

• The caller hears when picking up the handset a special dial tone (English stutter -tone or tone called MWI ).
• The caller hears when picking up the handset a brief announcement before the normal dial tone. The use of an announcement allows a fax machine to recognize a normal dial tone and still transmit a fax, especially with activated MWI.
• The subscriber hears, in addition to the expression with an announcement or MWI tone, yet a short ringtone.
• The participant will receive a text message, especially in ISDN devices. Especially with ISDN devices, the MWI information can be transmitted in the functional DSS1 protocol. The representation ( LED turn on or text message and / or ring tone ) on the ISDN unit itself is device-specific.
• The telephone set of the participant receives an FSK signal transmitted that turns an LED on the phone. This option can be used only with analog connections and is known as VMWI (English Visual Message Wait Indication).

In mobile networks, especially the call notification via SMS used because here has the necessary device-specific characteristics on the participant side. However, it involves no technical mediation feature, since alone the transmission using the SMS service is provided.

Calls by SMS

In a German mobile networks, the network operator the Call info via SMS established since 2005 in the customer activate the mains supply is answering called SMS notification to subscribers of missed calls, which in this case taking place non-availability announcement is provided to the caller usually in a paid connection bill.

Roaming

In mobile networks, it is often possible to make phone calls to foreign networks and to be available ( roaming). These are based on agreements between the network operators.