Two people can say "origination" and mean two different invoices, so keep the call path in view. A caller (or a PBX) originates a call. The network that serves the called number terminates that call. Every wholesale minute has at least those two roles, plus optional transit. Inbound to your DID is, from the caller's carrier's point of view, termination to you (or to your provider). Outbound from your trunk is origination by you (or by your provider on your behalf).
Two vocabularies for the same call
Enterprise invoices and STIR/SHAKEN use the call-path sense: origination is placing, termination is completing. Some VoIP wholesale decks flip the labels relative to the VoIP customer. Both appear in the industry. Read the column header on the rate deck before comparing two providers.
| Vocabulary | Your customer dials your DID (inbound) | You dial a customer (outbound) |
|---|---|---|
| Call path (this article, STIR/SHAKEN OSP/TSP) | Far-end originating carrier places. Your network terminates the call to the DID. | You (your provider) originate. The customer's carrier terminates. |
| Some VoIP wholesale interconnect decks | Sold as "origination": the PSTN hands the call to the VoIP provider | Sold as "termination": the VoIP provider hands the call to the PSTN |
Voice: who originates, who terminates
| From a business with DID +1 415 … | Call direction | Carrier language | Who typically pays whom |
|---|---|---|---|
| A customer dials your DID | Inbound to you | The customer's originating carrier places the call. Your provider is the terminating carrier (or pays a terminating partner). | The originating side pays termination (directly or via bill-and-keep / tandem arrangements). You often pay your provider a per-minute inbound (termination) rate plus the DID. |
| You dial a customer | Outbound from you | Your provider is the originating service provider. The customer's carrier terminates. | You pay outbound (origination) minutes. Your provider pays the terminating network. |
| Someone dials your toll-free number | Inbound to you, billed inverted | Toll-free origination: the 800 subscriber pays. RespOrg / toll-free provider pays originating LECs for the call. | You pay inbound toll-free minutes (often higher than local inbound). The caller does not pay a long-distance charge for the 8XX call in the classic U.S. model. |
Why inbound to a DID is termination
The called number is the termination target. Completing a call to +1 415 555 0100 is terminating traffic to that number, regardless of whether the owner thinks of it as "we received a call." Providers sell "inbound minutes" because they are accepting termination (and then delivering media to your PBX or CPaaS app). Providers sell "outbound minutes" because they are originating into the PSTN or peer networks. A SIP trunk usually meters both.
- Number ownership and termination are linked: the carrier of record for a DID is who other networks expect to pay (or dip) for completion.
- Porting moves which network terminates that number. During a port, dual-termination mistakes cause one-way failed inbound.
- STIR/SHAKEN: the originating service provider signs. The terminating service provider verifies. Same two roles as billing, different artifact (a PASSporT, not a CDR rate).
SMS: MO and MT
Messaging uses parallel vocabulary. Mobile originated (MO) is a message sent from a handset (or from an application acting as the sender on a local number, in A2P terms often treated as application-originated). Mobile terminated (MT) is a message completed to a handset. An inbound customer text to your business number is MT toward that DID from the wireless network's point of view, and it is inbound traffic from yours. An outbound notification you send is MT toward the customer's phone. Carrier billing for A2P SMS is mostly per-MT (you pay to complete to the handset), plus 10DLC / campaign fees. MO (keywords, STOP, customer replies) is the reverse hop.
| Hop | Voice analog | SMS analog | Business-typical invoice line |
|---|---|---|---|
| Place / send | Call origination (outbound voice) | Application-originated / A2P send (often discussed as MT to the destination handset) | Outbound minutes or outbound SMS (per-message MT) |
| Complete / receive | Call termination (inbound to your DID) | MO from the handset to your number, or inbound webhook | Inbound minutes or inbound SMS (sometimes bundled, sometimes per-MO) |
| Toll-free exception | Toll-free voice: subscriber pays for inbound | Toll-free texting: similar "subscriber pays" program, separate from 10DLC long codes | Toll-free inbound voice and TFN message rates |
What a rate deck is actually pricing
- Outbound / origination deck
- Price to place a call, usually by destination (NANP, on-net, international country code). E.164 is the key.
- Inbound / termination deck
- Price to receive a call on your numbers, often cheaper for local DIDs than for toll-free.
- Transit
- A middle carrier that is neither the OSP nor the TSP. You see this on least-cost routing, not on a simple hosted-PBX bill.
- Jurisdiction
- U.S. intra-state vs interstate vs international still appear on some decks because legacy access regimes differ. VoIP interconnection has narrowed but not erased that.
The same roles on the identity plane
STIR/SHAKEN reuses originating and terminating service provider on purpose. Billing CDRs and PASSporT signatures should describe the same call. If your CPaaS originates outbound but a downstream gateway re-signs C-level, analytics at the terminating carrier will not match what your invoice suggests. Ask who the originating carrier of record is for SHAKEN, not only who sends the bill.
How to read an invoice
- Inbound voice minutes on a local DID: termination to those numbers.
- Outbound voice minutes: origination from your trunk, priced by destination.
- Toll-free inbound: origination charges in the 8XX model (you pay).
- Outbound SMS: MT completion to wireless subscribers (plus 10DLC program cost).
- Inbound SMS: MO to your numbers, if not bundled.