SIP Trunk Setup for Voyced – Grandstream IP PBX (UCM Series)

Connect your Grandstream UCM telephone system to Voyced to make and receive calls using your business telephone number.

This guide covers the UCM6300 and UCM6300 Audio series, including the UCM6301, UCM6302, UCM6304 and UCM6308 models.

It also applies to older UCM6200 and UCM6510 systems, although some menu names may differ.

What You'll Need

Before starting, make sure you have:

• Administrator access to your Grandstream UCM.

• At least one working telephone extension.

• An active Voyced telephone number.

• Your Voyced SIP username and Service Password.

• A working internet connection.

Voyced SIP details

Replace the example username and password with your own Voyced credentials.

You can find your DID under Cloud PBX / IP Centrex > Phone Lines in your Voyced Hosted IPPBX. Select the wrench icon beside your number.

Your Service Password is available under My Profile > Settings.

The Service Password is different from your Voyced website login password.

Requirements Before You Begin

1. Confirm your Grandstream UCM has internet access.

2. Make sure it can connect to sip.voyced.eu using UDP port 5060.

3. Check that your firewall permits the RTP audio traffic required by your UCM. Use the port range configured on your system.

4. If your UCM is behind a router, check its NAT settings under PBX Settings > SIP Settings > NAT.

5. Make sure at least one extension is registered and can make internal calls.

For a UCM behind NAT, check that External Host contains the appropriate public address and Local Network Address contains your internal network range.

Keep your existing working network settings where possible.

Choose the correct SIP trunk type

Grandstream offers several SIP trunk types.

For a standard Voyced account, select:

Register SIP Trunk

This allows your Grandstream UCM to authenticate and register with Voyced using your DID and Service Password.

Do not select Peer SIP Trunk or Account SIP Trunk for this setup.

SIP Trunk Setup

Step 1: Log in to your Grandstream UCM

1. Open your web browser.

2. Enter your Grandstream UCM's management address.

3. Log in using your administrator credentials.

On current UCM6300 firmware, the SIP trunk settings are under:

Extension/Trunk > VoIP Trunks

On older UCM firmware, the menu may appear as:

PBX > Basic/Call Routes > VoIP Trunks

Step 2: Create the Voyced SIP trunk

1. Open VoIP Trunks.

2. Click Add or Add SIP Trunk.

3. Select Register SIP Trunk.

Enter:

If your firmware provides a separate SIP server port field, enter 5060.

Use your actual Voyced DID for both Username and Auth ID.

Enable Need Registration. Without registration, Voyced may not be able to deliver incoming calls to your UCM.

Leave other settings at their defaults.

Step 3: Configure Caller ID and SIP options

In the same trunk configuration, check the following settings:

The From User setting may appear under advanced trunk settings.

For a standard installation with one Voyced number, use that number as your outbound Caller ID.

If you use several authorised numbers, you can configure Direct Outward Dialling (DOD) rules for individual extensions.

Caller ID settings on your UCM do not automatically authorise another number on Voyced.

Step 4: Configure audio codecs

Open the trunk's advanced settings.

Find Codec Preference.

Use the following priority:

1. PCMA (G.711 A-law).

2. PCMU (G.711 u-law).

G.729 can also be used where your UCM and the complete call route support it.

For initial testing, PCMA and PCMU are recommended.

Leave other media settings unchanged unless your installation requires a specific adjustment.

Step 5: Save and check registration

1. Click Save.

2. Click Apply Changes at the top of the UCM interface.

3. Allow the configuration to update.

Open:

System Status > Dashboard

Find the trunk status information.

Your Voyced SIP trunk should show Registered.

On some firmware versions, you can also view the registration state from the VoIP Trunks page.

If the trunk does not register, check your SIP username, Service Password, server address and network connection.

Step 6: Create an inbound route

An inbound route determines where calls to your Voyced number should go.

For example, you may send incoming calls to:

• An extension.

• A ring group.

• An IVR telephone menu.

• A call queue.

• Another supported destination.

To configure the route:

1. Open Extension/Trunk > Inbound Routes.

2. Select your Voyced trunk.

3. Click Add.

On older firmware, use PBX > Basic/Call Routes > Inbound Routes.

Enter:

Grandstream uses an underscore at the start of dial patterns.

For example, if your incoming DID is 442035001234, enter:

_442035001234

The exact number must match the DID presented to your UCM on incoming calls.

If you have only one Voyced number and the incoming DID is not being recognised, you can test a broader pattern:

_X.

This matches incoming digit strings on the selected trunk. For a trunk carrying several telephone numbers, use specific DID patterns to route them separately.

Click Save, followed by Apply Changes.

Step 7: Create an outbound route

An outbound route determines which SIP trunk the UCM uses for external calls.

1. Open Extension/Trunk > Outbound Routes.

2. Click Add.

On older firmware, use PBX > Basic/Call Routes > Outbound Routes.

Enter:

The pattern _00X. matches international numbers beginning with 00.

Set Strip to 0 so the UCM does not remove any digits.

Leave Prepend empty.

Make sure the extensions allowed to use this route have the required International privilege level.

National and local calls

If you also want to make national or local calls through Voyced, create additional dial patterns appropriate to your country's numbering plan.

Use the matching privilege level for each route.

Keep any existing emergency call routing configured separately for your location and telephone service.

Click Save and Apply Changes.

Step 8: Configure voicemail access

Your Voyced voicemail number is:

1233

To allow extensions to access Voyced voicemail through the SIP trunk:

1. Open Extension/Trunk > Outbound Routes.

2. Add a route for the pattern _1233.

3. Select the Voyced trunk.

4. Set Strip to 0.

5. Leave Prepend empty.

6. Set a suitable privilege level.

7. Save and Apply Changes.

Check that 1233 does not conflict with an existing Grandstream feature code.

Your UCM also has its own voicemail system. You may continue using that instead if you prefer to keep voicemail within your PBX.

Step 9: Configure additional Voyced numbers

If you have several Voyced telephone numbers, the setup depends on how those numbers are supplied.

If each number has separate SIP credentials, you can create a separate registered SIP trunk for each account.

If several DIDs are delivered through one Voyced SIP account, you may use the same trunk with separate inbound routing rules.

Grandstream also supports trunk groups for managing several accounts using the same SIP server.

For initial setup, start with one working registered trunk before adding further numbers.

Test Your Connection

Once your Voyced trunk shows Registered, complete these tests.

Test 1: Outgoing calls

1. Pick up a telephone connected to a UCM extension.

2. Dial an external telephone number.

3. Confirm the call connects.

4. Check that audio works in both directions.

5. Verify the Caller ID displayed to the recipient.

Test 2: Incoming calls

1. Call your Voyced number from another telephone.

2. Confirm the Grandstream UCM receives the call.

3. Check that the inbound route sends it to the correct destination.

4. Answer the call and check audio.

Test 3: International calls

Voyced requires all international calls to use:

00 + Country Code + Telephone Number

For example:

00442035000202

Confirm the UCM sends the complete number, including the leading 00.

The outbound route must not strip those digits.

Test 4: Voicemail

Dial:

1233

Confirm that you reach your Voyced voicemail service.

If you use the UCM's own voicemail system instead, test that separately.

Test 5: Simultaneous calls

If your Voyced service supports multiple simultaneous calls, test the expected call capacity.

The available number of calls depends on your Voyced service.

A higher call limit in the Grandstream settings does not increase your available Voyced call capacity.

Troubleshooting

The SIP trunk does not register

Check:

Do not use your Voyced website login password.

After correcting the settings, click Save and Apply Changes.

Incoming calls do not work

• Confirm the trunk is registered.

• Check the inbound route selects the Voyced trunk.

• Check the DID Pattern.

• Confirm the selected extension, ring group or IVR works.

• Review your firewall and network settings.

If your UCM receives the call but does not route it, check which DID appears in the incoming call information.

The DID Pattern must match that value.

Outgoing calls do not work

• Check that your extension matches the outbound route.

• Confirm its privilege level allows the route.

• Check that the route uses the Voyced trunk.

• Verify the dialled number.

• Check your available Voyced call credit.

• Confirm the destination is permitted.

International calls fail

Check that:

• The dialled number begins with 00.

• The outbound pattern is _00X..

• The extension has International calling privileges.

• Strip is set to 0.

• Prepend is empty.

For example, 00442035000202 must reach Voyced unchanged.

No audio or one-way audio

Check the Grandstream NAT configuration under:

PBX Settings > SIP Settings > NAT

Confirm the external address and local network details are correct.

Also check:

• The RTP ports configured on your UCM.

• The corresponding firewall rules.

• Your telephone extensions' audio settings.

• The available codecs.

Start with PCMA and PCMU.

If your router uses SIP ALG, disable it where appropriate.

Incorrect Caller ID

Grandstream can control Caller ID through trunk settings, DOD rules and extension settings.

Check which number the UCM sends through Voyced.

Only use numbers authorised on your Voyced service.

To request another Caller ID:

1. Log in to your Voyced client area.

2. Open a sales support ticket.

3. Use the subject Outbound Caller ID adjustment.

4. Provide your Voyced DID and the number you want displayed.

Numbers outside your Voyced account require proof of ownership and additional verification.

Voyced Internal DIDs and extension numbers must not be used as public Caller ID numbers.

View registration and call information

Open:

System Status > Dashboard

Check the SIP trunk registration status.

For further diagnosis, current UCM6300 firmware provides network troubleshooting tools under:

Maintenance > Network Troubleshooting

You can use the available network tests and Ethernet Capture to investigate a failed connection or call.

When contacting Voyced Support, provide the date, time, destination and result of the affected call.

Do not share your Service Password.

Final Tips

• Use sip.voyced.eu as your primary SIP server.

• Select Register SIP Trunk, not Peer SIP Trunk.

• Use your Voyced DID as Username and Auth ID.

• Enable SIP registration.

• Use UDP port 5060 for the standard connection.

• Start with PCMA and PCMU audio codecs.

• Configure separate inbound and outbound routes.

• Use the 00 prefix for every international call.

• Keep Strip set to 0 when international numbers must pass unchanged.

• Check extension privileges before allowing international calls.

• Use only authorised outbound Caller ID numbers.

• Check your network and firewall settings if registration or audio fails.

• Test incoming and outgoing calls after changing trunk or routing settings.

Once registration, routing and audio have been tested successfully, your Grandstream UCM telephone system is ready to use with Voyced.

Last updated: 27/10/2026

© Voyced
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.