Inbound trunks#
Inbound trunks deliver calls received on your DIDWW phone numbers to your phone system, a mobile or landline number, or the phone.systems™ cloud PBX. Use this section to set up, manage, and monitor inbound call delivery.
Key features#
Deliver calls to your SIP system, a landline or mobile number, or the phone.systems™ cloud PBX.
Use trunk groups for failover and load balancing.
Filter unwanted calls with number lists.
Set capacity limits to control simultaneous calls through trunks and trunk groups.
Monitor traffic and investigate failed calls with inbound analytics.
What is an inbound trunk?#
A DID number is the phone number that callers dial. An inbound trunk tells DIDWW where to deliver the calls received on that number. A DID number must be assigned to an inbound trunk before DIDWW can deliver its calls.
Multiple DID numbers can use the same trunk and share its delivery settings. To use several destinations for the same numbers, combine trunks in a trunk group.
Choose a trunk type#
Trunk type |
Delivers calls to |
Best for |
What you need |
|---|---|---|---|
Your IP PBX, SBC, softphone, or voice application, using SIP. |
Businesses with their own phone system or voice platform. |
A SIP endpoint that DIDWW can reach, or one that registers with DIDWW. |
|
A landline or mobile number, through the DIDWW termination network. |
Forwarding calls to a phone without SIP equipment. |
A destination phone number. Forwarded calls are charged per minute. |
|
The phone.systems™ cloud PBX, where call flows, IVRs, and users are managed. |
Teams that want a hosted PBX without managing equipment. |
An active phone.systems™ subscription. |
How inbound calls work#
When a caller dials your DID number, the public telephone network routes the call to DIDWW. DIDWW delivers the call through the trunk or trunk group assigned to that DID number.
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sequenceDiagram
autonumber
participant caller as Caller
participant network as Telephone network
participant didww as DIDWW
participant destination as Destination
caller->>network: Dial DID number
network->>didww: Route call to DIDWW
Note over didww: Find the trunk or trunk group<br/>assigned to the DID number
didww->>destination: Deliver call through the trunk
Reliability and failover details
Inbound call delivery is protected at two levels: inside the DIDWW network, and between DIDWW and your systems. For details, see Service failover and load balancing.
DIDWW network redundancy
Multiple Points of Presence (PoPs): DIDWW receives and delivers calls from PoPs on several continents. PSTN interconnections terminate at more than one PoP. If a PoP or interconnection becomes unreachable, traffic for the affected number ranges is diverted to a healthy PoP automatically.
Redundant SBCs: Each PoP uses redundant load balancers and session border controllers (SBCs). A failed node is removed from service while the others continue to handle calls.
Resilient connectivity: Each PoP uses several IP transit providers and direct interconnections at major Internet Exchanges.
24/7 monitoring: A Network Operations Center monitors the platform and responds to incidents.
Failover to your systems
DNS SRV: Publish several SIP servers behind one host name. DIDWW tries another server when one does not respond. See DNS SRV failover.
Trunk groups: Combine SIP and PSTN trunks. DIDWW tries the next trunk when a call attempt fails, or spreads calls between trunks. See Trunk group failover. For SIP or PSTN destinations, prepare the member trunks, then create a trunk group and assign the group to your DID number instead of an individual trunk.
Get started#
Prepare your DID number and call destination, then assign the trunk and test incoming calls.
1. Get a DID number#
Start by finding an available number you want to buy. You can also review the payment methods before purchasing.
Search available numbers, review prices and service options, and buy one if you need a new DID number.
Choose a payment method and add funds if your prepaid balance is insufficient for the purchase.
2. Choose your call destination#
Choose one option based on where you want to receive calls.
Create a SIP trunk for your PBX, SBC, softphone, or application.
Create a PSTN trunk to forward calls to a landline or mobile number.
Use the trunk named phone.systems, created automatically with an active subscription.
3. Assign and test#
Assign first, then complete your destination setup and test an incoming call.
Assign the prepared trunk or trunk group to your DID number.
After assignment and destination setup, call your DID number and confirm the test call in Inbound Call Logs.
Configure, manage, and monitor inbound calls#
Deliver calls to your SIP infrastructure, choose a routing method, and configure call handling.
Forward calls to a landline or mobile number.
Deliver calls to the phone.systems™ cloud PBX.
Combine trunks for failover and load balancing.
Allow or reject calls by calling number or prefix.
Select the DIDWW Points of Presence used for SIP call delivery.
Find the formats callers dial to reach toll-free numbers and UIFNs.
Review inbound call logs, SIP response codes, statistics, and reports, and export or stream call records.
Identify why an inbound call failed and find troubleshooting guidance.
Technical references#
Look up the tabs, filters, fields, values, and actions on the Inbound Trunks page.
Find signaling addresses, media addresses, codecs, and firewall requirements.