1. How does Multiline TAPI work?
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Welcome!
The Multiline TAPI service enables the integration of the NFON telephone system into the respective customer environment. The basis of the Multiline TAPI is the NFON CTI API.
Subject to change
Version 1 / 08/2025 (EN)
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Multiline TAPI enables bidirectional data exchange between the computer TAPI interface and various end devices.
Customers can choose freely between desktop phones or the NFON Cloud Telephony App Suite.
The possible uses of TAPI are complex and depend on the respective application scenario or the third-party software used. The suitability of NFON Multiline TAPI must be assessed for each respective use case.
The Multiline TAPI has only been tested and approved for use with one terminal per extension.
More complex usage scenarios must be assessed by the customer on their own initiative. NFON accepts no responsibility for this.
The Multiline TAPI is currently provided with the following scope of services:
CTI outbound | From phone outbound | Inbound |
Make Call | Dial - Call seen | Offering |
Hangup during Ringback | Dial - Call with Ringback Hangup | Connected |
Hangup during Connected | Dial - Call connected Hangup | Hangup |
To use the Multiline TAPI service, you will require CTI API access data. You can request it via email at vertrieb@nfon.com or auftragsbearbeitung@dt-standard.de.
The email must contain the following information:
K account
Approximate number of extensions in the K account
Completed declaration of consent (Template declaration of consent)
Customer contact email address
Partner email address
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The Windows TAPI Server performs the following tasks:
Hosting the third-party TAPI Service Provider (TSP),
Providing communication for the control of telephony from/to the telephone system via the TAPI service provider.
Company telephones are connected directly to the NFON telephone system via the cloud. This connection ensures that the phones are operational and managed by the cloud (e.g. call forwarding, ringtones etc.).
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The telephony is controlled via the computer using Outlook or a CRM system. The connection between the computer and telephony is made via the TAPI service provider.
This makes so-called "telephony devices" available, which can be used to control calls from the PC. For example, you can start calls at the click of a mouse or to automatically display information about the caller when a call comes in.
The Multiline TAPI enables various application scenarios which are described in the sections:
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A multi-line TAPI interface is used to integrate telephony functionalities into a server-based CRM system. This enables central administration and use of several TAPI lines on one server, facilitating flexible and scalable communication between the telephone system and the CRM system.
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Setting up the Multiline TAPI on the server
The Multiline TAPI is installed on the same central server on which your CRM system is running (see Multiline TSP Setup) or with which the CRM can communicate. This TAPI interface acts as middleware between the PBX and the operating system and provides standardised TAPI lines.
Via the TAPI server, the TAPI drivers provide an overview of all available extensions or exchange lines that are provided via the PBX.
Connecting to the CRM system
The server-based CRM system is connected to the Multiline TAPI server via a TAPI-capable integration (e.g. a corresponding CRM module or plug-in). The connection is usually made via a local or network accessible TAPI provider. The CRM registers with the TAPI server and receives access to the available lines.
Configuring the TAPI lines
Within the CRM system, the TAPI lines are assigned to the respective users, workstations or roles. This is typically done via the CRM administration interface, where the lines provided by the TAPI server are displayed.
The configuration usually includes:
Assignment of TAPI lines to CRM users
Definition of call events (e.g. pop-ups for incoming calls)
Configuration of dialling rules and trunk codes
Logging and analysing call data (e.g. in the customer contact history).
Functionality during operation
After successful configuration, the CRM system communicates with the TAPI server in real time. Incoming and outgoing calls are recognised and processed in the CRM. This enables, among other things:
Automatic opening of the customer data record for incoming calls
Click-to-dial functionality from the CRM
Call history and assignment of telephone activities to customers.
As the TAPI lines are managed centrally on the server, no local TAPI installation is required on the client workstations. This simplifies maintenance and increases the stability of the solution in the corporate environment.
In modern IT architectures, a combination of centrally managed multi-line TAPI and a locally installed CRM system is quite common. The aim is to give the CRM access to central telephony functions via the local TAPI interface – without a direct physical connection to the PBX.
Architecture overview
The Multiline TAPI is installed on a central Windows server (see Multiline TSP Setup) and connected to the PBX. All available lines are provided via a TAPI driver (TSP) (see User line configuration).
The TAPI server makes these lines available for remote access in the network.
The Windows TAPI component is used on the client PC to connect to the TAPI server. To do this, remote TAPI access is activated, e.g. with the command tcmsetup /c <server name> (see Client configuration).
The locally installed CRM system uses the Windows TAPI interface to access the line provided by the server, as if it were available locally.
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More details
Centralised provisioning: The TAPI server manages all lines centrally. These lines are assigned to the PBX via the Multiline TSP.
Remote connection: On the client, tcmsetup is used to register the TAPI server as the source for lines. The assigned line then appears in the local TAPI dialogue.
CRM integration: The local CRM accesses the line via the TAPI interface. Functions such as caller identification, dialling by click (click-to-dial), logging and call windows are available.
A server application can be connected via TAPI for multiple clients. To do this, multiple instances of the NFON third-party Multiline TSP are run on the CRM system server.
Each instance communicates with a customer NFON system. The CRM system has access to all instances and thus to TAPI lines of all customers. The CRM system distributes call-related information to the appropriate clients.
The CRM clients themselves do not use TAPI. Instead, they are informed of incoming calls via the CRM system. When a client initiates an outgoing call, it informs the CRM system, which triggers the dialling via TAPI.
An integrated authorisation management system ensures that the clients of one customer do not have access to the lines of any other customer.
Setting up TSP instances
As this feature is currently in beta, we are happy to assist with testing. Please send enquiries to integration@nfon.com.
To create multiple instances of the NFON Multiline TSP:
Install TSP.
Download the verpatch.exe tool.
Copy the files below to a working folder:
• verpatch.exe
• C:\Program Files (x86)\NFON\NFON TAPI\Tools\CreateInstance.batOpen the command line window as administrator.
Switch to the working folder.
Please note that the script also works without administrator rights, but the created TSP instance must then be copied manually to C:\Windows\System32.Execute the script as follows:
1. Call: CreateInstance.bat
2. Enter the desired tenant name, e.g. K6732
3. If the file C:\Windows\System32\NFONTSP.TSP is missing, you will be asked for the source TSP file.
⇒ The new instance is created and, when executed as administrator, automatically copied to C:\Windows\System32.Open the provider list (Windows Phone and Modem options).
Select Add.
Select a new instance (NFON third-party TAPI <instance name>).
Configure a new instance.
Please note that
• The access data (K account, API password) is stored in the telephone and modem options.
• Each instance connects to its own NFON system.
Now all configured TSP instances and associated TAPI lines are available to the CRM system (e.g. from C4B).
Depending on the application scenario, it may be necessary to configure the client or a third-party system in addition to installing and configuring the Multiline TSP.
The following configuration is required for communication between the TAPI server and TAPI client.
Windows Client – Outgoing rules
Rule name Protocol Port(s) Destination Purpose:
Allow RPC Endpoint Mapper TCP 135 Telephony Server IP RPC Service Discovery
Allow SMB TCP 445 Telephony Server IP access to named pipes, files
Allow RPC Dynamic Ports TCP 49152-65535 Telephony Server IP RPC communication to TAPI services
Telephony Server – Incoming rules
Rule name Protocol Port(s) Source Purpose:
Allow RPC Endpoint Mapper TCP 135 Client Subnet IPs RPC Service Discovery
Allow SMB TCP 445 Client Subnet IPs access to named pipes, files
Allow RPC Dynamic Ports TCP 49152-65535 Client Subnet IPs RPC communication to TAPI services
Telephony Server – Outgoing rules to Domain Controller
Rule Name Protocol Port(s) Destination Domain Controller IP(s) Purpose
Allow LDAP TCP 389 Domain Controller IP(s) Active Directory queries
Allow LDAP UDP 389 Domain Controller IP(s) LDAP Discovery (optional)
Allow Kerberos TCP 88 Domain Controller IP(s) authentication
Allow DNS UDP/TCP 53 DNS Server IP(s) Name resolution
Allow SMB TCP 445 Domain Controller IP(s) domain-related file and named pipe access
Installing the Multiline TAPI
Download NFONTAPI.msi.
Double-click NFONTAPI.msi to start the installation.
Starting the configuration
Open the Control Panel.
Select Phone and Modem.
Switch to the Advanced tab.
Select Configure.
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Finalising the configuration
Enter the CTI API access data (see Requesting access data). It includes your user name (K account) and password (CTI API password).
Select the Number format in which the incoming TAPI events are to be signalled.
Select the Line name format which defines the format in which the TAPI lines are displayed in TAPI applications.
Select the level of detail under Debug output in which the log files are saved. Level 0 is the lowest level and only needs to be adjusted for support cases.
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Phone number formats
In the TSP configuration, you can set the format in which the telephone numbers are to be signalled in TAPI events (see previous section).
This not only determines how, for example, the caller number of an incoming call is displayed in the TAPI application, but also ensures that a TAPI application, such as a CRM system, finds the right contact for the calling phone number in its contact database.
The TSP offers four variants to choose from:
International
The numbers are signalled as a complete international number with country code and plus sign. For example:
Semperoper Dresden: +49303514911705
Sydney Opera House: +61292507111International without plus sign
The numbers are signalled as a complete international number with country code but without plus sign. For example:
Semperoper Dresden: 49303514911705
Sydney Opera House: 61292507111Phone book format
Numbers in your own country are signalled as long-distance numbers with a long-distance prefix, international numbers as international numbers with an international prefix. The selection of this format requires a correct location configuration in the Windows dialling rules (see below).
Examples for users in Germany:
Semperoper Dresden: 0303514911705
Sydney Opera House: 0061292507111Phone book format, international
The numbers are signalled as international numbers with an international dialling code. The selection of this format requires a correct location configuration in the Windows dialling rules (see below).
Examples for users in a country with international dialling code 00:
Semperoper Dresden: 0049303514911705
Sydney Opera House: 0061292507111
Testing
Once the configuration is complete, the TAPI is available for testing. You can carry out the test using the Windows Dialer (C:\Windows\System32\dialer.exe) or, alternatively, Phone.exe.
To perform the test in Windows Dialer:
1. Select the line to be tested. Please make sure that the format of the line corresponds to the configured format.
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2. Log in to Cloudya with the same extension. In this example, it is extension 18.
3. Enter the desired phone number to be dialled. When you press the Dial button, extension 18 will ring and as soon as it is answered, the call to the destination number will be established.
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Windows server operating systems can distribute the TAPI lines of the NFON Multiline TSP to individual clients of a Windows domain.
TAPI applications on the clients can then access the TAPI line(s) assigned to the respective client.
The user is assigned to the TAPI line on the server. This can be done via a graphical user interface (tapimgmt.msc) or with the help of an XML interface.
Important
Only assign the TAPI line(s) to a user who is authorised to control them.
The graphical user interface is suitable for quick and easy manual management of smaller environments.
Activating NFON Multiline TSP
Start the interface on the Windows server Start > Run.
Enter tapimgmt.msc.
Click Enter.
In the console view, click the + icon next to Telephony to open the window.
Click NFON TSP.
Click Properties.
Configuring NFON Multiline TSP
Click NFON TSP.
Click the line number or name in the detail view.
Click Edit user in the action menu.
Click Add.
In the Look in box, select the domain that contains the user.
Select the user from the list.
Click Add.
The XML interface is suitable for large environments and automated configuration. The details can be found on the Microsoft support page: https://learn.microsoft.com/dede/windows-server/administration/windows-commands/tsecimp
This page describes both what an initial configuration looks like and subsequent changes.
Here is an example XML for the initial configuration:
<UserList>
<User NoMerge="1">
<DomainUser>NFON\MAUERSBERGERM</DomainUser>
<FriendlyName> Marius Mauersberger</FriendlyName>
<LineList>
<Line>
<Address>1254</Address>
</Line>
</LineList>
</User>
<User NoMerge="1">
<DomainUser> NFON\KONDERM</DomainUser>
<FriendlyName> Max Konder</FriendlyName>
<LineList>
<Line>
<Address>185</Address>
</Line>
</LineList>
</User>
</UserList>
<DomainUser> = Windows user incl. domain<FriendlyName> = Display name (optional)<Line> = TAPI Line, if this is unique on the system. If not, <PermanentID> entries must be used here.
For further information and configuration options, go to Microsoft documentation.
To be able to use TAPI on the client, you need to extablish a connection to the TAPI server. Activation is carried out with tcmsetup as described in the Microsoft documentation at https://learn.microsoft.com/de-de/windows-server/administration/windows-commands/tcmsetup.