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Receive and Place Calls

This guide explains how to send and receive calls using CarrierX.

  • To receive inbound calls, you must have a phone number assigned to a trunk group that is connected to an endpoint.
  • To place outbound calls, you must have an endpoint with valid authentication credentials.

Configuring Firewall​

To send and receive calls, your system must be able to communicate with CarrierX SIP infrastructure.

  1. Navigate to Configure > Endpoints in the portal.
  2. Open the System Gateway endpoint (automatically created for your account).
  3. Locate the Endpoint Addresses section and copy the listed IP addresses. These are the IP addresses to add to your firewall.

Configure your firewall to:

  • Allow SIP signaling from these IP addresses
  • Allow RTP/media traffic (media may originate from dynamic IPs)
note

The System Gateway endpoint is system-generated and exists in every account.

Receiving Calls​

To receive inbound calls, your phone number must be properly routed.

Requirements​

  • A phone number is assigned to a trunk group
  • The trunk group is associated with an endpoint
  • Your firewall allows inbound SIP signaling (see Configuring Firewall)
How It Works

When someone calls your phone number:

  1. CarrierX receives the call
  2. The system matches the number to a trunk group
  3. The trunk group routes the call to the associated endpoint
  4. Your SIP system (PBX, softswitch, or application) receives the call

Placing Calls​

By default, CarrierX uses proxy authentication to place outbound calls.

Step 1: Get Credentials​

In Configure > Endpoints, click the third-party endpoint that you would like to make outbound calls from.

Use the following credentials to authenticate your outbound calls:

  • Username: Endpoint SID
  • Password: VoIP Token

Step 2: Check Available Phone Numbers​

  1. Open your endpoint
  2. Click the Assigned Phone Numbers tab

This tab shows the phone numbers associated with the trunk group connected to this endpoint.

If the tab is empty

This means no phone numbers are currently associated with the endpoint's trunk group.

To fix this:

  1. Navigate to Configure > Phone Numbers
  2. Select a phone number
  3. Click Edit
  4. Assign the phone number to the appropriate trunk group
  5. Click Save

After this, the number will appear in the Assigned Phone Numbers tab.

Requirements​

  • A configured endpoint
  • Valid authentication credentials
  • A caller ID (phone number) associated with your account
info

Phone numbers do not need to be assigned to a trunk group for outbound calls, but they must belong to your account.

How It Works

When your system places a call:

  1. Your SIP system sends a request to CarrierX
  2. CarrierX authenticates the request using your endpoint credentials
  3. The call is routed to the destination (PSTN or SIP endpoint)

Verification Checklist​

Use this checklist to confirm your setup is working correctly:

  • Inbound calls reach your SIP system
  • Outbound calls are successfully initiated
  • Authentication succeeds (no 401 or 403 errors)
  • Audio is present in both directions

Next Steps​

You can now send and receive calls using CarrierX.

For more information, refer to: