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Connect Grandstream UCM to TelecomsXchange

Guide 13 of 285-minute readUpdated 23 October 2026

In short: On a Grandstream UCM6300 or UCM63xx, add a VoIP trunk of type Peer SIP Trunk to sip01.telecomsxchange.com over UDP with heartbeat detection off, and authorise the UCM's public IP on your TelecomsXchange account. Add an outbound rule that strips 00 and prepends the tech prefix, so calls leave as 80039#447700900123, and inbound rules for your E.164 numbers.

Grandstream UCM to a purchased route
  1. Your UCMPeer SIP trunk, identified by IP
  2. then, 80039#447700900123, TelecomsXchangesip01, UDP 5060
  3. Seller's routeThe route you purchased
On this page
  1. Before you start
  2. How do I send calls to TelecomsXchange?
  3. How do I receive calls from TelecomsXchange?
  4. How do I receive calls on numbers I bought?
  5. How do I test it?
  6. What if something goes wrong?
  7. References
  8. Common questions

This guide connects a Grandstream UCM6300 series (UCM6301, UCM6302, UCM6304, UCM6308) or UCM63xx PBX to TelecomsXchange with a peer SIP trunk: outbound calls to a purchased route, and inbound calls on numbers you bought or routes you sell. For the full list of TelecomsXchange values, see Connect a SIP platform.

Warning

TelecomsXchange does not accept SIP REGISTER. Create a Peer SIP Trunk, not a Register SIP Trunk. The UCM is recognised by its source IP address.

Before you start#

  • A SIP account with the UCM's public IP, for example 203.0.113.10, in IP Address or Additional Allowed IPs.
  • A purchased route and its tech prefix from My Interconnections, for example 80039#. In this guide TECH_PREFIX stands for that value.
  • A UCM with a static public IP, or a fixed NAT address with SIP and RTP ports forwarded.
  • To receive calls on numbers you bought: a phone number whose SIP endpoint points at the UCM, for example sip:14165551234@203.0.113.10:5060.

How do I send calls to TelecomsXchange?#

  1. Go to Extension/Trunk → VoIP Trunks and click Add SIP Trunk.
  2. Enter:
Field Value
Type Peer SIP Trunk
Provider Name TelecomsXchange
Host Name sip01.telecomsxchange.com (port 5060 is the default)
Transport UDP
Keep Trunk CID / Caller ID Number Your caller ID, if you want one per trunk
  1. Save, then edit the trunk and open Advanced Settings:
Field Value Why
Codec Preference The codecs your route supports, for example G.729, PCMU, PCMA TelecomsXchange doesn't transcode
DTMF Mode RFC4733 (RFC2833) Standard in-RTP DTMF
Enable Heartbeat Detection No TelecomsXchange answers OPTIONS only within a call
SRTP No TelecomsXchange doesn't support SRTP

Click Save and Apply Changes.

  1. Go to Extension/Trunk → Outbound Routes and click Add. Enter:
Field Value
Calling Rule Name TCXC
Pattern _00X.
Privilege Level International (or the level your users have)
Use Trunk TelecomsXchange
Strip 2
Prepend 80039# (your TECH_PREFIX)

A user who dials 00447700900123 sends 80039#447700900123 to TelecomsXchange. If users dial with +, add a second rule with Pattern _+X. and Strip 1. The UCM uses the first matching rule from the top, so place these above broader rules.

The UCM may send the # as %23 in the Request-URI; TelecomsXchange decodes it.

Tip

To pick routes per destination, add one outbound rule per destination pattern (for example _0044X.) with that route's tech prefix in Prepend. Or prepend a routing group prefix such as 444101# and let TelecomsXchange choose.

NAT. If the UCM is behind NAT, go to PBX Settings → SIP Settings → NAT, set External Host to your public IP (203.0.113.10) and Local Network Address to your LAN, and forward UDP 5060 and the RTP range (shown under PBX Settings → RTP Settings).

How do I receive calls from TelecomsXchange?#

Calls on numbers you bought, and on routes you sell, come from 174.136.44.213 over UDP, from source ports 5060 to 5072, with the number in E.164 format such as 14165551234.

  1. Allow 174.136.44.213 on the firewall in front of the UCM for UDP 5060 and the RTP range. If you use the UCM's own firewall rules (System Settings → Security Settings), add an accept rule for 174.136.44.213.
  2. The UCM matches an incoming INVITE to the peer trunk by its source address. sip01.telecomsxchange.com resolves to 174.136.44.213, so calls land on the TelecomsXchange trunk. If they don't, set the trunk's Host Name to 174.136.44.213.
  3. In the trunk's Advanced Settings, keep DID Mode on Request-line, where TelecomsXchange puts the number.
  4. Go to Extension/Trunk → Inbound Routes, select the TelecomsXchange trunk and click Add. Set DID Pattern to the number as it arrives, for example _14165551234, and choose the destination (an extension, ring group, queue or IVR). Use _X. with a default destination to catch every number. Click Save and Apply Changes.
  5. If your route has an Outgoing Prefix or strips digits (Edit Route → Outgoing Number Translation Parameters), match that format, or use the inbound rule's Strip to remove it.

The UCM is a PBX. As a seller, it can terminate calls to its own extensions and numbers, but it isn't designed to carry wholesale transit traffic on to another carrier.

How do I receive calls on numbers I bought?#

Set the number's SIP Endpoint (Primary) in DID Settings to the UCM, for example sip:14165551234@203.0.113.10:5060. TelecomsXchange sends the INVITE from 174.136.44.213 with 14165551234 in the Request-URI, and the inbound rule for that DID sends it on.

How do I test it?#

  1. Go to Maintenance → Troubleshooting → Ethernet Capture and start a capture.
  2. Place a call from an extension to 00447700900123.
  3. Stop the capture, open it in Wireshark (Telephony → VoIP Calls), and look for the INVITE to 80039#447700900123 (or 80039%23447700900123) and the reply.
  4. On the UCM, check the call under CDR → CDR. In the TelecomsXchange portal, watch it in Live Calls and find its SIP code in Logs → CDR (Voice).

What if something goes wrong?#

You see What to do
401 or 407 from TelecomsXchange, then the call fails The UCM's source IP isn't authorised, so TelecomsXchange asks for credentials a peer trunk can't send. Add the public IP to IP Address or Additional Allowed IPs.
403 Forbidden The source IP isn't authorised. Compare the public IP in the capture with the account; check the account isn't blocked or out of balance.
404 Not Found Missing or wrong tech prefix, or +/00 left in the number. Check Strip and Prepend on the outbound rule and the Request-URI in the capture.
408 Request Timeout No reply from sip01. Check outbound UDP 5060 on your firewall and that the UCM resolves sip01.telecomsxchange.com.
503 Service Unavailable The route is blocked or failed on the seller's side. Check My Interconnections; try another route or a routing group.
Trunk shows unreachable Enable Heartbeat Detection is on. Turn it off; TelecomsXchange answers OPTIONS only within a call.
One-way or no audio Set External Host and Local Network Address in the SIP NAT settings and forward the RTP range.
Inbound calls rejected The call isn't matched to the peer trunk. Set Host Name to 174.136.44.213 and check the firewall.
Inbound call arrives but goes nowhere No inbound rule's DID Pattern matches the number as it arrives; check the format and any Outgoing Prefix on your route.

References#

Common questions

Can a Grandstream UCM register to TelecomsXchange?

No. TelecomsXchange is peering only and does not accept REGISTER, so use a Peer SIP Trunk, not a Register SIP Trunk. The UCM is recognised by its public IP address.

Can the UCM use the VoIP login and password instead of its IP?

Use IP authentication. A UCM peer SIP trunk has no username or password fields; those belong to register trunks, which send REGISTER. If the UCM's public IP changes, add the new one under Additional Allowed IPs.

Should I turn on Enable Heartbeat Detection?

No. It sends SIP OPTIONS to check the peer, and TelecomsXchange answers OPTIONS only within a call, so the trunk would look unreachable.

Where does the tech prefix go?

In the outbound rule: Pattern _00X. with Strip 2 and Prepend 80039# turns 00447700900123 into 80039#447700900123.

Can a Grandstream UCM register to TelecomsXchange?
No. TelecomsXchange is peering only and does not accept REGISTER, so use a Peer SIP Trunk, not a Register SIP Trunk. The UCM is recognised by its public IP address.
Can the UCM use the VoIP login and password instead of its IP?
Use IP authentication. A UCM peer SIP trunk has no username or password fields; those belong to register trunks, which send REGISTER. If the UCM's public IP changes, add the new one under Additional Allowed IPs.
Should I turn on Enable Heartbeat Detection?
No. It sends SIP OPTIONS to check the peer, and TelecomsXchange answers OPTIONS only within a call, so the trunk would look unreachable.
Where does the tech prefix go?
In the outbound rule: Pattern _00X. with Strip 2 and Prepend 80039# turns 00447700900123 into 80039#447700900123.

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This guide matches platform build 83b4ebc9. Markdown version.