SIP Trunk Setup for Unify OpenScape Business

Use Voyced as an external SIP provider

This guide explains how to connect your Voyced telephone number and SIP trunk to Unify OpenScape Business, allowing your business to make and receive telephone calls through Voyced.

OpenScape Business supports external SIP providers through its Internet Telephony Service Provider (ITSP) configuration.

The connection uses standard SIP registration with your Voyced username, service password and SIP server.

This manual covers OpenScape Business V3, including the X1, X3, X5, X8 and S systems. Older V2 installations use a similar configuration process, although some menus and settings may differ.

What You'll Need

Before you begin, make sure you have:

• Administrator access to your OpenScape Business system

• Access to the Web-Based Management interface (WBM)

• Administrator permissions with the Advanced profile

• A working internet connection

• At least one configured extension and telephone

• Available SIP trunk licences

• An active Voyced telephone number

Your Voyced SIP details:

Replace the example username and password with your actual Voyced service details.

Requirements Before You Begin

Your OpenScape Business installation must support ITSP connections.

Before starting, confirm:

• The system has sufficient licensed SIP trunk channels.

• Your internet connection can support the required number of simultaneous calls.

• The PBX can resolve sip.voyced.eu using DNS.

• The network permits SIP signalling and RTP audio traffic.

• SIP ALG is disabled on your router if it interferes with calls.

• Your internal extensions and call destinations are configured.

Recommended audio codecs:

• G.711 A-law / PCMA

• G.711 μ-law / PCMU

Voyced expects destination telephone numbers in international format without a leading +.

Example:

442012345678

OpenScape Business uses its own number conversion rules. We will check these after configuring the SIP trunk.

SIP Trunk Setup Steps

1. Log in to OpenScape Business

1. Open your OpenScape Business WBM interface.

2. Log in with an administrator account.

3. Confirm your account uses the Advanced profile.

4. Open Setup.

5. Navigate to Wizards → Central Telephony.

6. Find Internet Telephony.

7. Click Edit.

The Internet Telephony wizard manages external SIP providers.

OpenScape Business supports up to eight active ITSPs.

If other SIP providers are already configured, leave their settings unchanged.

2. Check Your Location Settings

The first wizard screen displays your telephone location details.

Enter or confirm:

Example for a UK installation:

Enter country and area codes without international prefixes or a leading +.

For example:

44

Not:

+44

These location settings help OpenScape Business construct telephone numbers for incoming and outgoing calls.

If your PBX already has correctly configured location information, retain it.

Click OK & Next.

3. Enable Internet Telephony

The wizard displays:

Provider configuration and activation for Internet Telephony

1. Clear No call via Internet.

2. Review the existing provider list.

3. Check whether Voyced is already configured.

4. If not, click Add.

This opens the configuration for a new Internet Telephony Service Provider.

The system includes predefined provider profiles.

For Voyced, create a custom provider configuration.

4. Create the Voyced Provider

In the new provider configuration, enter:

Select the generic or default base template if your firmware offers it.

Do not use the profile of an unrelated telephone provider without reviewing its settings.

The Provider Name is limited to 10 characters.

Voyced fits this limit.

Next, configure the SIP server details.

5. Configure the SIP Server

In the provider configuration, locate Gateway Domain Name.

Enter:

sip.voyced.eu

Next, configure Provider Registrar.

The registrar handles SIP account registration.

The 120-second interval is the standard OpenScape Business default.

Keep it initially. If the registrar requires a different interval, use the accepted value.

6. Configure the SIP Proxy

Locate Provider Proxy.

Enter:

The proxy handles outgoing SIP requests.

For this configuration, the proxy and registrar use the same hostname.

Next, review the optional proxy settings.

A separate outbound proxy is not needed for the standard connection.

Leave the optional proxy and STUN settings disabled unless your network requires them.

For installations behind NAT, additional network configuration may be needed if the PBX cannot establish reliable SIP signalling or audio.

Click OK & Next.

7. Create Your Voyced SIP Account

The wizard now displays the Internet Telephony Stations associated with the provider.

1. Click Add.

2. Open the account configuration.

3. Enter your Voyced SIP details.

The Internet Telephony Station identifies your Voyced SIP account.

The Authorization Name is the username used during SIP authentication.

For the normal Voyced configuration, both fields contain the same value.

Example:

442012345678

Use your Voyced service password in both password fields.

8. Select the Telephone Number Assignment Method

OpenScape Business supports several methods of assigning external telephone numbers.

For a standard business SIP trunk, select:

Use public number (DID)

This is the preferred arrangement when one SIP account handles one or several telephone numbers.

With DID-based routing:

• The SIP account handles registration.

• Incoming telephone numbers are matched to the configured DIDs.

• Each DID can have its own internal destination.

• Different extensions may present their authorised external telephone numbers.

Under Default Number, enter your primary Voyced telephone number.

Example:

Your-Voyced-DID

The Default Number is used for outgoing calls when the calling extension does not have a suitable external caller ID.

Leave optional MEX settings empty unless you specifically use the Mobile Extension feature.

If your installation uses multiple ITSP routes, configure the appropriate route prefixes as required.

For a single Voyced account, no additional provider route is normally necessary.

Click OK & Next.

Alternative: Internal Number Assignment

Older systems or particular numbering plans may use:

Use internal number (Callno) / Single entries

This method maps individual provider telephone numbers to internal extensions.

It can be suitable when separate SIP registrations are required for individual telephone numbers.

For the standard Voyced arrangement, use the public number (DID) method instead.

9. Review the SIP Account

The wizard displays an overview of the configured Internet Telephony Stations.

Confirm:

Check the details.

Click OK & Next.

With public number (DID) mode, the individual number-to-extension assignments are configured separately.

10. Configure Simultaneous Calls

The next wizard screen controls the available bandwidth and number of simultaneous calls.

Locate:

Upstream up to (Kbps)

Enter the actual upload bandwidth available to your PBX.

For example:

OpenScape Business calculates the maximum number of supported internet calls from the available bandwidth.

If several ITSPs are configured, the wizard also allows you to distribute the available lines between providers.

Assign the number of lines you want to make available to Voyced.

The number must not exceed your available SIP trunk licences or the calling capacity of your Voyced service.

For example:

These values are examples only.

Click OK & Next.

11. Configure Special Telephone Numbers

The wizard displays a list of special telephone numbers.

These may include:

• Emergency services

• Directory services

• Other national service numbers

Review the existing entries.

For each number, select the appropriate route under Dial over Provider.

Keep your existing emergency call routing unless you have confirmed that the intended SIP route supports the required emergency services and location handling.

For normal international calls, the Voyced trunk will be selected through the outbound routing configuration.

Click OK & Next.

12. Check the SIP Registration Status

The wizard now displays the configured ITSP status.

Find:

Voyced

Click Display Status.

Check the connection and registration information.

A successful registration confirms the PBX has authenticated with Voyced.

If registration fails, review:

• Registrar hostname

• Proxy hostname

• SIP username

• Authorization Name

• Password

• DNS resolution

The wizard also provides Restart ITSP.

Use this function after correcting registration settings.

It restarts the provider connection and attempts registration again.

Avoid deactivating and reactivating a working provider simply to refresh its registration, as this can affect manually adjusted routing settings.

13. Configure Outgoing Trunk Priority

Continue through the Internet Telephony wizard.

The system may open the CO Trunk ISDN / Analog / ITSP configuration.

This determines which external connection is selected for outgoing calls.

For example:

If Voyced should handle your normal outgoing telephone calls, select it as the preferred ITSP route.

If you use several providers, retain the routing arrangement that matches your business requirements.

The exact trunk seizure settings depend on your country and existing PBX numbering plan.

Finish the wizard.

14. Assign SIP Trunk Licences

Open:

License Management → CO trunks

Locate the SIP trunks section.

Find:

License demand for number of simultaneous Internet calls in this node

Enter the number of simultaneous SIP trunk calls required.

For example:

4

The system checks the number against your available licences.

OpenScape Business requires SIP trunk licences for external ITSP calling.

If you already use other SIP providers, account for the combined licence demand.

Click OK & Next to save.

The licence count and the number of lines assigned in the Internet Telephony wizard must be consistent.

15. Configure Audio Codecs

To review the voice settings:

1. Open Expert Mode.

2. Navigate to Telephony Server → Voice Gateway.

3. Select Codec Parameters.

Find the available audio codecs.

For the Voyced connection, use:

If your version allows codec priority adjustments, place G.711 A-law first.

DTMF Settings

OpenScape Business supports out-of-band DTMF using RFC2833/4733.

Use this method for keypad input with IVR menus and voicemail.

If a specific DTMF payload value is required, it can be configured under the codec parameters.

For the initial setup, leave DTMF payload negotiation at its default.

Save the changes.

16. Configure Incoming DID Numbers

If you selected Use public number (DID), the incoming telephone numbers are assigned to stations.

In WBM:

1. Open Expert Mode.

2. Navigate to the station configuration under Telephony Server.

3. Select the extension that should receive incoming calls.

4. Locate Direct inward dialing.

5. Enter the DID assigned to that extension.

6. Save the changes.

Example:

The DID field must match the numbering scheme used by your OpenScape Business configuration.

Depending on the location data and PABX number, the PBX may expect only the DID portion rather than the complete international telephone number.

For example, where the country code, area code and company prefix are already configured separately, enter the remaining extension-specific DID digits.

Check the received number and configured numbering scheme before changing existing station DIDs.

17. Configure Additional Incoming Numbers

If several telephone numbers belong to your Voyced SIP account, assign them to their destinations.

For example:

Each number must have an appropriate DID assignment.

If your organisation uses a call group, AutoAttendant or another shared destination, configure the relevant group or virtual station as the DID destination.

The exact setup depends on your existing OpenScape Business call handling.

For multiple numbers delivered through one SIP account, you do not need a separate registration for every number.

18. Configure Outbound Number Formatting

Voyced expects telephone numbers in full international format without a leading +.

Example:

442012345678

OpenScape Business uses Least Cost Routing (LCR) to determine how outgoing telephone numbers are converted.

Open:

Expert Mode → Telephony → LCR

On some software versions, the menu appears under:

Expert Mode → Telephony Server → LCR

Review:

• Dial Plan

• Dial Rule

• Routing Table

Confirm that outgoing calls through Voyced use the required number format.

Number Format Example

If a user dials:

00442012345678

and 00 is your international access prefix, the outbound routing must convert it to:

442012345678

before sending the SIP call to Voyced.

Similarly, if your PBX uses an external access code, that code must be removed before sending the call.

Do not assume the number shown on the telephone is identical to the number sent in the SIP INVITE.

Provider Number Format

OpenScape Business supports different number formats.

For Voyced, the desired international format is:

International without prefix

The provider profile supports settings such as:

These settings help the system represent numbers without a leading international access prefix.

The final called-number format also depends on the LCR dial rules.

The caller ID must likewise be an authorised telephone number in the format accepted by Voyced.

Because LCR settings depend on your existing numbering plan, check the current rules before making changes.

19. Configure Outbound Calling Permissions

OpenScape Business uses Classes of Service to control which extensions may make external calls.

In Expert Mode, open the LCR configuration.

Select Classes of Service.

Check the extensions that should use the Voyced SIP trunk.

Confirm their assigned class permits the required outbound route.

For example:

Keep destination restrictions appropriate to your organisation.

If an extension can make internal calls but cannot reach Voyced, check its Class of Service and LCR routing permissions.

20. Configure Firewall and NAT

Your OpenScape Business system must communicate with:

sip.voyced.eu

Recommended network settings:

OpenScape Business uses its internal media gateway for RTP audio.

The required RTP port range depends on your installed system and configuration.

If Your PBX Is Behind NAT

OpenScape Business supports NAT traversal.

For the initial configuration, retain the existing working NAT settings.

The system can determine whether STUN is required, depending on its network configuration.

If registration succeeds but audio fails:

1. Check the PBX's public IP address handling.

2. Review the firewall's UDP session handling.

3. Confirm the required RTP traffic can pass.

4. Review the OpenScape Business NAT settings.

5. Use STUN only if appropriate for your network.

OpenScape Business does not support every NAT type, including symmetric NAT in its standard STUN arrangement.

Avoid changing the network configuration unless testing identifies a problem.

Testing Your Setup

Registration Test

1. Open Setup → Wizards → Central Telephony.

2. Start the Internet Telephony wizard.

3. Open Display Status.

4. Locate Voyced.

5. Confirm registration has succeeded.

The expected result is an active, registered ITSP connection.

If the registration is unsuccessful, use the provider diagnostics before continuing.

Inbound Test

1. Call your Voyced telephone number from an external mobile telephone.

2. Confirm the call reaches OpenScape Business.

3. Check the correct DID is identified.

4. Verify the assigned extension or group rings.

5. Answer the call.

6. Check audio in both directions.

If you have several Voyced telephone numbers, test each one separately.

Outbound Test

1. Pick up a telephone connected to OpenScape Business.

2. Dial an external telephone number using your normal PBX dialling method.

3. Confirm the call uses the Voyced SIP trunk.

4. Check that the destination rings.

5. Verify two-way audio.

6. Confirm the correct caller ID appears.

Example destination number:

442012345678

Check that the SIP request sent to Voyced contains the full international number without a leading + or an unwanted access prefix.

Troubleshooting

SIP Registration Fails

Check:

• SIP server is sip.voyced.eu

• Registrar is enabled

• Registrar port is 5060

• Proxy hostname is correct

• Internet Telephony Station contains your Voyced username

• Authorization Name is correct

• Service password is correct

• DNS resolution works

Open Display Status in the Internet Telephony wizard.

Use Restart ITSP after correcting the configuration.

401 or 407 Error

These responses indicate an authentication challenge.

An initial challenge is normal during SIP registration.

If authentication repeatedly fails, check:

• SIP username

• Authorization Name

• Service password

• Authentication realm

• Whether the PBX sends another authenticated REGISTER request

403 Error

Check:

• Account status

• Authentication details

• Outbound calling permissions

• Caller ID authorisation

• Any account restrictions

404 Error

Check:

• Destination telephone number

• LCR dialling rules

• International prefix handling

• SIP Request-URI

• Incoming DID matching

• Which system returned the error

If the outgoing number includes 00 or another unwanted prefix, review the LCR number conversion.

Incoming Calls Do Not Ring

Check:

• SIP registration status

• DID assignment

• Location data

• Station configuration

• Incoming called-number format

• Call forwarding settings

• Destination availability

If the SIP INVITE reaches the PBX but does not match a destination, compare the received called number with the assigned DID.

Remember that OpenScape Business may store the DID separately from the country, area and PABX number.

Incoming Calls Reach the Wrong Extension

Check:

• Assigned DID

• Station number

• Shared or duplicate DID assignments

• AutoAttendant configuration

• Call groups

• Incoming call forwarding

For multiple telephone numbers, confirm each DID has a unique intended destination.

Outbound Calls Fail

Check:

• SIP registration

• Trunk licence availability

• Assigned ITSP lines

• LCR dial plan

• Routing table

• Dial rule

• Class of Service

• Caller ID

• Available calling credit

• Simultaneous call capacity

Outbound Number Has the Wrong Format

The final number sent to Voyced must contain the country code without a leading +.

For example:

442012345678

Open:

Expert Mode → Telephony → LCR

Check the dial rule used by the Voyced route.

If your PBX uses 00 for international calls, confirm the rule removes that prefix before sending the call.

One-Way Audio

Check:

• RTP connectivity

• Firewall settings

• NAT handling

• Media gateway configuration

• SDP media addresses

• Codec negotiation

• SIP ALG

SIP registration and RTP audio use different network connections.

Successful SIP registration does not automatically confirm audio connectivity.

Calls Disconnect After Approximately 30 Seconds

Check:

• SIP acknowledgement delivery

• NAT handling

• Firewall timeouts

• Session timers

• SIP signalling addresses

Trunk Is Registered but No Calls Can Be Made

Check:

1. Available SIP trunk licences

2. Assigned ITSP lines

3. Outbound route priority

4. LCR dial plan

5. Extension Class of Service

6. Number formatting

Trunk Shows Unavailable

Open the Internet Telephony wizard.

Select Display Status and review the provider information.

The Diagnose function provides additional connection and configuration details.

Check the registration and network information.

If needed, restart the Voyced ITSP connection using Restart ITSP.

Caller ID Is Incorrect

Check:

• Default Number in the ITSP account

• Station DID settings

• Outgoing caller ID format

• LCR and route configuration

• Authorised telephone numbers

If an extension does not have a suitable external caller ID, OpenScape Business may use the configured Default Number.

Final Tips

• Keep the SIP server set to sip.voyced.eu.

• Use your Voyced telephone number as the SIP username and authorization name.

• Use your Voyced service password for registration.

• Configure Voyced as a custom ITSP.

• Enable SIP registration.

• Use the public number (DID) assignment method for standard business SIP trunks.

• Assign the correct number of simultaneous calls.

• Confirm sufficient SIP trunk licences are available.

• Use G.711 A-law and G.711 μ-law for audio compatibility.

• Configure each incoming DID for the correct destination.

• Check the LCR dial plan and outgoing number conversion.

• Use full international telephone numbers without a leading +.

• Verify outbound caller ID presentation.

• Test registration, inbound calls and outbound calls separately.

Unify OpenScape Business supports third-party SIP providers through its Internet Telephony wizard.

With the correct SIP account, provider profile, licences and routing configuration, you can connect OpenScape Business to Voyced for incoming and outgoing business telephone calls.

Last updated: 27/10/2026

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All information provided is copyrighted and purely informative in nature. It is maintained by Voyced with the greatest of care using reliable sources only.
Given the fast evolution of the telecom sector, Voyced does not offer any guarantee about the accuracy and completeness of the information offered. 
We explicitly do not give anyone permission to use this information in any other way than to inform themselves about what (legal) requirements there may be and they need to comply with when registering Services and/or DIDs with Voyced.