Connect an AudioCodes Mediant SBC to TelecomsXchange

An AudioCodes Mediant SBC (Mediant 500 to 9000, and Mediant VE or Software SBC) connects to TelecomsXchange as a SIP peer: one Proxy Set and IP Group for TelecomsXchange, routing rules in each direction, and a manipulation for the tech prefix. The steps use the Web interface of firmware 7.4 and later; the same tables exist in the CLI and INI file. For every TelecomsXchange value in one place, see Connect a SIP platform.

Before you start#

• A SIP account on TelecomsXchange with the SBC's public WAN IP, for example 203.0.113.10, or a VoIP login and password from Edit Account → Add SIP Digest Auth.
• A purchased route and its tech prefix from My Interconnections, for example 80039#. In this guide, TECH_PREFIX stands for that value, and VOIP_LOGIN and VOIP_PASSWORD for the account's VoIP Login and VoIP Password.
• The SBC's WAN IP interface, a Media Realm for it, and a working connection to your PBX, Teams or Zoom on the other side.
• To sell: a route with IP Address:Port set to the SBC, for example 203.0.113.10:5060, and the values in Interconnect Info.

How do I send calls to TelecomsXchange?#

All tables are under Setup → Signaling & Media.

1. SIP Interface (Core Entities → SIP Interfaces): use or add an interface on the WAN network interface with UDP Port 5060 and Application Type SBC, for example WAN-UDP. Give it the WAN Media Realm.
2. Proxy Set (Core Entities → Proxy Sets): add one named TCXC:
   • SBC IPv4 SIP Interface: WAN-UDP.
   • Proxy Keep-Alive: Disable. TelecomsXchange answers OPTIONS only within a call.
   • In its Proxy Address child table, add sip01.telecomsxchange.com:5060 with Transport Type UDP. It resolves to 174.136.44.213.
3. IP Group (Core Entities → IP Groups): add one named TCXC:
   • Type: Server.
   • Proxy Set: TCXC. Media Realm: the WAN realm.
   • IP Profile: a profile with the codecs the route supports (G.729, G.711) and no SRTP (SBC Media Security Mode Not Secured).
   • Classify By Proxy Set: Enable is fine when only this IP Group uses 174.136.44.213; otherwise use the Classification table below.
4. Routing (SBC → Routing → IP-to-IP Routing): add a rule from your PBX, Teams or Zoom IP Group, matching the destinations the route covers (for example Destination Username Pattern 44), with Destination Type IP Group and Destination IP Group TCXC.
5. Tech prefix (SBC → Manipulation → Outbound Manipulations): add a rule:

The Request-URI leaves the SBC as sip:80039#447700900123@sip01.telecomsxchange.com. Numbers must reach this rule in E.164 without + or 00; strip + with an inbound manipulation on the source IP Group (for Teams, numbers arrive as +447700900123).

Digest variant. If the SBC sends from an IP that isn't on the account, add an Account (SIP Definitions → Accounts):

With Register: No, the SBC doesn't register; it answers TelecomsXchange's 401 or 407 challenge on the INVITE with these credentials.

How do I receive calls from TelecomsXchange?#

Calls on routes you sell, and on numbers you bought, 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 your firewall for UDP 5060 and the WAN Media Realm's port range. On the SBC, a Firewall (access list) rule can restrict SIP on the WAN interface to it.
2. Classification (SBC → Classification Table): unless Classify By Proxy Set is on, add a rule with Source SIP Interface WAN-UDP, Source IP Address 174.136.44.213, Action Type Allow and Source IP Group TCXC. Calls from other addresses on that interface fall through to your other rules or are rejected.
3. Routing (SBC → Routing → IP-to-IP Routing): add a rule with Source IP Group TCXC to the IP Group of your PBX, carrier, Teams or Zoom. Route by Destination Username Pattern if different numbers go to different places.
4. Teams expects numbers in +E.164; add + with an outbound manipulation toward the Teams IP Group (Prefix to Add +).
5. If your TelecomsXchange route adds an Outgoing Prefix (Edit Route → Outgoing Number Translation Parameters), remove it with an Inbound Manipulation on IP Group TCXC (Remove From Left).

How do I receive calls on numbers I bought?#

Set the number's SIP Endpoint (Primary) in DID Settings on TelecomsXchange to the SBC, for example sip:14165551234@203.0.113.10:5060. The call is classified into IP Group TCXC and routed by the IP-to-IP rule above to the PBX, Teams user or Zoom user that owns the number.

How do I use it with Microsoft Teams or Zoom Phone?#

Microsoft Teams Direct Routing and Zoom Phone BYOC (Bring Your Own Carrier) only connect to a certified SBC over SIP TLS with SRTP. TelecomsXchange doesn't offer TLS or SRTP, so it can't be the TLS endpoint for Teams or Zoom. The Mediant SBC sits in between:

• Teams or Zoom side: TLS on port 5061, SRTP, a certificate for your SBC's FQDN, and the vendor's own IP Group and IP Profile, as in AudioCodes' configuration notes.
• TelecomsXchange side: the UDP Proxy Set and IP Group in this guide, with RTP. The SBC converts SRTP to RTP between the two IP Profiles.

See Connect Microsoft Teams and Connect Zoom Phone for the Teams and Zoom side.

How do I test it?#

1. Send the SBC's syslog to the Syslog Viewer (or open the Web interface's Message Log under Troubleshoot) and enable SIP debug; or start a Debug Recording and open it in Wireshark.
2. Place a call to a number covered by the route.
3. In the log, look for the INVITE to 80039#447700900123 toward 174.136.44.213 and the reply. The Monitor tab's active calls view shows calls in progress.
4. On TelecomsXchange, watch the call in Live Calls and find its SIP code in Logs → CDR (Voice).

What if something goes wrong?#

References#

• AudioCodes: Configuring Proxy Sets
• AudioCodes: Configuring Classification Rules
• AudioCodes: Configuring SBC IP-to-IP Routing Rules
• AudioCodes: Configuring IP-to-IP Outbound Manipulations
• AudioCodes: Configuring Registration Accounts