Grandstream UCM SIP Trunk Configuration
Simtex SIP Trunks from $4.99/month
Business-grade SIP trunking with geo-redundant infrastructure, crystal-clear audio, and Australian-based support. Pay-as-you-go or unlimited plans available.
SIP Servers:
- West Coast (AU):
siptcp.simtex.com.au - East Coast (AU):
siptcpeast.simtex.com.au
Choose the server closest to your UCM. Grandstream UCM supports TCP and TLS transport options on the Advanced Settings tab.
Do not expose your UCM to the public internet. In 99.9% of cases you do not need any ports forwarded on your router or firewall to connect to Simtex. If you are unsure, speak to us first.
UCM RemoteConnect users: If you manage your UCM6300 remotely via Grandstream's UCM RemoteConnect / GDMS cloud portal, the SIP trunk configuration is identical. RemoteConnect provides remote access to the same web GUI — SIP trunks connect directly from the UCM to Simtex regardless of how you access the admin panel.
UCM6300 menu path: On some UCM6300 firmware versions, the menu path may be PBX → Basic/Call Routes → VoIP Trunks instead. Both paths lead to the same configuration page.
Trunk types explained: Grandstream offers two trunk types. Register SIP Trunk is the correct choice for Simtex — the UCM authenticates with your account credentials and registers with our SIP servers. Peer SIP Trunk is for IP-based authentication (no credentials) and is used for interconnecting PBX systems or providers that whitelist your IP.
Keep Trunk CID: When checked, the trunk's own Caller ID is used for all outbound calls on this trunk. When unchecked, individual extensions can send their own caller ID. Check this initially to ensure your main DID is always presented, then uncheck later if you need per-extension caller ID.
Save before Advanced: You must click Save on the Basic Settings first before the Advanced Settings tab becomes available for editing. After saving, click Apply Changes at the top of the page.
East Coast? Replace
siptcp.simtex.com.au with siptcpeast.simtex.com.au in the Host Name field if your UCM is located on the East Coast of Australia (NSW, VIC, QLD).G.711 A-Law (PCMA) is the standard codec for Australian PSTN interconnection. It provides toll-quality audio at 64kbps with zero transcoding overhead. Always place it first. Grandstream uses
PCMA and PCMU as the codec names.PPI and PAI are mutually exclusive. You cannot enable both Send PPI Header and Send PAI Header at the same time on a Grandstream UCM. Only one of these SIP identity headers can be active per trunk. For Simtex, enable Send PAI Header (P-Asserted-Identity).
Heartbeat Detection sends SIP OPTIONS packets at the configured interval to monitor trunk availability. This helps the UCM detect a trunk failure quickly and trigger failover to a backup trunk if configured.
Route ordering matters. The UCM processes outbound routes from top to bottom and uses the first matching pattern. Use the arrow buttons to reorder routes so more specific patterns (like emergency
000) are above general catch-all patterns.Recommended Dial Patterns for Australian Numbering
| Description | Pattern | Strip | Prepend | Privilege | Example |
|---|---|---|---|---|---|
| Local (8-digit) | _XXXXXXXX | 0 | Local | 94883344 | |
| National / Mobile | _0XXXXXXXXX | 0 | National | 0412345678 | |
| Emergency | 000 | 0 | Internal | 000 | |
| 1300 / 1800 Numbers | _1[38]00XXXXXX | 0 | National | 1300888519 | |
| 13 Numbers (6-digit) | _13XXXX | 0 | National | 131313 | |
| International (0011) | _0011. | 0 | International | 001161894883344 |
International dialling: If you do not need international calls, simply leave out the
0011 dial pattern. This is the simplest way to prevent unauthorised international dialling and potential toll fraud. You can also restrict this by setting the Privilege Level to International and only granting that privilege to authorised extensions.Pattern prefix: Grandstream dial patterns must be prefixed with an underscore
_ when using wildcards. X matches any digit 0–9, N matches 2–9, Z matches 1–9, and . matches one or more characters.Caller ID validation: Simtex validates outbound caller IDs against your account. Only DIDs allocated to your trunk will be transmitted — any other number is replaced with your main trunk number automatically.
Trunk not registering? Check these common issues:
- Verify your account number (
214XXXXXXX) and password — copy/paste to avoid typos - Ensure Transport is set to TCP on the Advanced Settings tab
- Confirm the From Domain matches the Host Name (
siptcp.simtex.com.au) - Check that Need Registration is ticked on the Basic Settings tab
- Check your firewall allows outbound TCP connections
- Try the alternate server (
siptcpeast/siptcp) in case of regional issues
Change default passwords immediately. Grandstream UCM ships with the well-known default credentials
admin / admin. Leaving these unchanged is one of the most common causes of PBX compromise.Common Questions
Register SIP Trunk. Simtex uses credential-based authentication. Your UCM registers with our SIP servers using your account number and password. Peer SIP Trunk is only for IP-based authentication where the provider whitelists your public IP.
Last updated 30 March 2026