Yeastar S-Series SIP Trunk Configuration

Overview

This guide walks you through configuring a Simtex SIP trunk on a Yeastar S-Series PBX (S20, S50, S100, S300) using a VoIP Register Trunk with TCP transport. The S-Series is Yeastar's established line of compact IP-PBX appliances with a straightforward web-based administration interface.

Yeastar S-Series PBX systems are reliable, cost-effective IP-PBX appliances ideal for small to mid-sized businesses — yeastar.com

What you'll need

• Your Simtex account number (e.g. 214XXXXXXX)
• Your Simtex SIP password
• Your allocated DIDs (phone numbers)
• Yeastar S-Series PBX with web GUI access

Step 1 — Create the SIP Trunk

1. Navigate to Settings → PBX → Trunks
2. Click Add
3. For Select Country, select General (Simtex is not in the pre-configured ITSP template list for the S-Series)
4. Set Trunk Type to Register Trunk

Step 2 — Trunk Settings

Configure the connection details for Simtex:

Basic Settings

Name:                Simtex-SIP
Trunk Status:        Enabled
Trunk Type:          Register Trunk
Protocol:            SIP
Transport:           TCP
Hostname/IP:         siptcp.simtex.com.au
Domain:              siptcp.simtex.com.au
Username:            214XXXXXXX
Password:            XXXXXXXX
Authentication Name: 214XXXXXXX
From User:           214XXXXXXX
Caller ID Number:    (your main DID, e.g. 61894883344)
Caller ID Name:      (your business name)

Step 3 — Advanced Settings

Click the Advanced tab and configure the following:

DID Number

Enter your DID numbers. Click + to add each DID in E.164 format without the + prefix (e.g. 61894883344). Tick DNIS Name to add a friendly label for each DID.

VoIP Settings

Qualify:             Enabled
DTMF Mode:           RFC4733 (RFC2833)
T.38 Support:        Disabled (unless you need fax)
Enable RTP Keep-alive: Enabled
Maximum Channels:    (your purchased channel count)

Inbound Parameters

Get Caller ID From:  P-Asserted-Identity
Get DID From:        Follow System

Outbound Parameters

P Asserted Identity: Default
Remote Party ID:     Default

Step 4 — Codec Configuration

Click the Codec tab within the trunk settings.

Move the following codecs from the Available list to the Selected list. Use the priority buttons to set this order:

Priority 1:  G711 a-law  (alaw)
Priority 2:  G711 u-law  (ulaw)

Remove any unnecessary codecs from the Selected list — a cleaner codec list speeds up call negotiation.

Click Save and Apply to save the trunk configuration.

Step 5 — Outbound Routes

Outbound routes tell your PBX which numbers are allowed to be dialled externally and which trunk to use.

1. Navigate to Settings → PBX → Call Control → Outbound Routes
2. Click Add
3. Enter a Name (e.g. “Simtex Outbound”)
4. Under Member Trunks, select your Simtex-SIP trunk
5. Under Member Extensions, select the extensions that should be allowed to make external calls
6. Configure Dial Patterns for Australian numbering (see table below)
7. Click Save and Apply

Step 6 — Inbound Routes

Inbound routes direct incoming calls on your DIDs to the correct destination.

1. Navigate to Settings → PBX → Call Control → Inbound Routes
2. Click Add
3. Enter a Name (e.g. “Main Line”)
4. Under Member Trunks, select your Simtex-SIP trunk
5. Under DID Pattern, enter the DID number in E.164 format (e.g. 61894883344) — or leave blank for a catch-all route
6. Set the Destination to the target extension, ring group, IVR, or queue
7. Click Save and Apply

Create a catch-all route first

Leave the DID Pattern blank to create a catch-all route. This handles any inbound DID that doesn't have a specific route — point it at your receptionist or main ring group.

Then add DID-specific routes

Create additional inbound routes for individual DIDs or DID ranges that need specific routing.

Testing Your Trunk

Once configured, verify everything works:

1. Check trunk status — navigate to Settings → PBX → Trunks and confirm the trunk shows a green “Registered” status
2. Make an outbound call — dial an external number from an extension and confirm two-way audio
3. Receive an inbound call — call one of your DIDs from a mobile and confirm it routes correctly
4. Verify caller ID — check your outbound caller ID displays correctly on the receiving end
5. Check voicemail — leave a voicemail to ensure DTMF tones are working correctly through the trunk

Security Hardening

After configuring your trunk, take these essential steps to secure your Yeastar PBX:

Disable SIP Guest Calls

1. Navigate to Settings → PBX → General → SIP
2. Scroll to the Advanced SIP settings
3. Set Allow Guest to No

Additional security measures

• Strong extension passwords — use the auto-generated passwords; do not simplify them
• IP auto-defense — Yeastar includes built-in brute-force protection; ensure it is enabled under Security → Security Rules
• Firmware updates — keep your PBX firmware up to date via Maintenance → Upgrade
• Channel limits — keep Maximum Channels on the trunk set to your actual requirement
• Disable unused services — turn off SSH, FTP, or other remote access protocols you don't use

Extension-Level Caller ID

By default, outbound calls present the Caller ID Number set on the trunk. To override per extension:

1. Navigate to Settings → PBX → Trunks
2. Edit your Simtex-SIP trunk
3. Under the Adapt Caller ID tab, configure rules to modify the caller ID for specific extensions or patterns

Alternatively, configure the trunk's Caller ID Number field with your main DID, and use outbound route overrides for specific routing needs.

The DID must be allocated to your Simtex account — you cannot present arbitrary numbers.

Need Help?

If you run into any issues configuring your Yeastar S-Series trunk, our support team can verify your trunk registration status from our side and assist with troubleshooting.

Contact Simtex Support